JP2006104543A - Method for reforming surface quality of copper wire or copper alloy wire used for manufacturing ultrafine wire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for reforming the surface quality of a copper wire or a copper alloy wire for manufacturing an ultrafine wire with a diameter of 20 μm or less, which does not form surface defects such as a scratch, a crack and a stamp of a copper powder on the surface of a wire, and does not cause the breaking of the wire when drawing the wire into the ultrafine wire. <P>SOLUTION: The method for reforming the surface quality of the copper wire or the copper alloy wire for manufacturing the ultrafine wire comprises the steps of: dissolving and removing the surface defect of the copper wire or the copper alloy wire; and plating it with copper or a copper alloy. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for modifying the surface properties of a copper wire or a copper alloy wire, which is a copper wire or a copper alloy wire for producing an ultrafine wire having a thickness of 20 μm or less, and prevents disconnection due to wire drawing.

  Wires and cables used as internal wiring of various electronic devices are required to have finer conductors as the electronic devices become smaller and lighter. Such an extra fine wire is usually manufactured by a capstan type wire drawing machine using a die, but depending on the surface properties of the supplied copper wire or copper alloy wire, disconnection occurs at the time of drawing. That is, if there is a foreign object or surface defect on the surface of a copper wire or copper alloy wire, the wire will not be able to withstand the die pulling tension during wire drawing, resulting in disconnection. For this reason, improvement of the shape of a die, the kind of lubricating oil, a wire drawing machine, etc. are examined. In addition, with respect to copper wires, copper alloy wires, and the like, surface properties such as mechanical properties and surface peeling treatment of the wires have been modified. However, surface defects are a major factor especially when trying to obtain ultrafine wires with a conductor diameter of 20 μm or less. That is, scratches, cracks, copper powder stamps, and the like on the surface of copper wires and copper alloy wires are problematic. Further, these surface defects have problems such as not only a disconnection problem at the time of wire drawing but also a decrease in adhesion when a metal plating layer is formed thereon.

In order to solve such problems, a peeling process is added in the middle of wire drawing processing, adjustment of drawing tension, examination of die shape and properties of lubricating oil, etc. have been studied. More solutions on the line were desired. Patent document 1 is seen regarding such a technique. That is, a step of coating a conductive metal element with a metal A or a resin A in a layered form to a thickness of 1 to 100% of the wire diameter of the conductive metal element, a step of reducing the diameter of the coated element wire, It consists of a step of removing the coating layer of the coated wire after the diameter reduction processing, and a step of coating the elemental wire (extra fine wire) from which the coating layer has been removed with a layer of metal B or resin B. By reducing the diameter after forming a metal or resin layer having a specific thickness on the metal strand, the conductive metal strand does not cause surface flaws or foreign matter mixed therein. However, in such a manufacturing method, since surface defects are not removed before coating with metal A or resin A, disconnection is particularly likely to occur when wire drawing is performed to 15 μm or less. Is not clean, the metal A or the resin B is not in close contact, and there is a possibility that the effect of preventing disconnection is small. Furthermore, since the removal process of the metal A or the resin A is required, it cannot be said that it is preferable from the viewpoint of cost. Furthermore, the surface of the conductive metal wire after the removal of the metal A or the resin A may cause surface roughness due to non-uniformity of deformability at the time of die compression when drawn. It may be considered that wire drawing for surface smoothing is required.
JP 2002-208323 A

  Therefore, the problem to be solved by the present invention is a copper wire or a copper alloy wire for producing an ultrafine wire, and the wire surface has no surface defects such as scratches, cracks, stamps of copper powder, and the like. An object of the present invention is to provide a method for modifying the surface properties of a copper wire or a copper alloy wire for producing an ultrafine wire having a thickness of 20 μm or less, which does not sometimes cause disconnection or the like.

  The problem to be solved is a copper wire or a copper alloy wire for manufacturing an extra fine wire as claimed in claim 1, wherein surface defects of the copper wire or the copper alloy wire are dissolved and removed. This is solved by adopting a method for modifying the surface properties of a copper wire or copper alloy wire for producing an ultrafine wire that performs copper plating or copper alloy plating.

  Moreover, as described in claim 2, the electrolytic bath is divided into two parts, an electrolytic polishing treatment tank and a plating treatment tank, by a partition made of an insulating material, each filled with an electrolytic solution containing copper ions, An electrode (cathode) connected to the negative side is disposed in the electrolytic polishing treatment tank, and an electrode (anode) connected to the positive side is disposed in the plating treatment tank. In this state, the copper wire or the copper alloy wire is disposed. The electrolytic polishing treatment tank and then the plating treatment tank are continuously passed, whereby the surface of the copper wire or the copper alloy wire is subjected to the electrolytic polishing treatment and subsequently the copper plating treatment or the copper alloy plating treatment is performed. This is solved by using a method for modifying the surface properties of a copper wire or copper alloy wire for producing ultrafine wires.

  Furthermore, as described in claim 3, the surface defect modification method of the copper wire or the copper alloy wire for producing the ultrafine wire according to claim 1, wherein the dissolution removal of the surface defect is an acid dissolution treatment. It is solved by.

  According to the present invention described above, after surface defects of the copper wire or copper alloy wire are dissolved and removed, the surface property modification of the copper wire or copper alloy wire for producing an ultrafine wire is then performed. Since the method is used, a copper wire or a copper alloy wire is obtained that is free from surface defects such as scratches, cracks, and copper powder stamps on the surface of the wire, and that disconnection or the like hardly occurs during wire drawing of ultrafine wires. In particular, the copper or copper alloy layer formed by the plating process has very few surface defects that are harmful during the wire drawing process, which contributes to the modification of the surface properties because it provides good wire drawing. For this reason, it is preferable as a copper wire or a copper alloy wire for producing an extra fine wire of 20 μm or less. Further, since the surface property modification treatment method is performed in a continuous process, it is possible to prevent contamination problems and trauma, and it can be performed in a relatively simple process.

  Also, the electropolishing bath is divided into two, an electropolishing bath and a plating bath, each filled with an electrolytic solution containing copper ions. (Anode) is placed in the tank, and in this state, copper wire or copper alloy wire is continuously electropolished and then plated, so there are no surface defects such as scratches, cracks, and stamps of copper powder on the wire surface. Thus, a copper wire or a copper alloy wire can be obtained in which disconnection or the like hardly occurs at the time of drawing the ultrafine wire. Further, the copper or copper alloy layer formed by the above-described plating treatment gives excellent wire drawing because there are very few surface defects that are harmful at the time of wire drawing, and copper wire or copper for producing ultrafine wires of 20 μm or less. Preferred as an alloy wire. Furthermore, since the surface property modification treatment is performed in a continuous process, it is possible to prevent contamination problems and trauma, and it is also useful in terms of cost because it can be performed continuously in a relatively simple process. Further, in such a surface property modification method, copper ions dissolved from the anode in each of the electrolytic polishing bath and the plating bath are deposited at the cathode, Therefore, the resistance value of the electrolytic solution does not change and the copper wire or copper alloy wire for producing the ultrafine wire can be obtained stably.

  In addition, by dissolving and removing the surface defects of copper wire or copper alloy wire with acid dissolution treatment, surface defects such as scratches, cracks, stamps of copper powder, etc. can be removed by a relatively simple method, and on top of that, good Since a simple plating layer can be formed, a copper wire or a copper alloy wire that does not cause disconnection or the like during the drawing process of an ultrafine wire is obtained. The copper or copper alloy layer formed by plating does not have surface defects that are harmful during wire drawing, so it provides good wire drawing, and as a copper wire or copper alloy wire for producing ultrafine wires of 20 μm or less. preferable. Further, since the surface property modification treatment is performed in a continuous process, contamination problems and trauma can be prevented, and the cost is practical.

  The present invention is described in detail below. The invention described in claim 1 is a copper wire or a copper alloy wire for producing an extra fine wire, wherein surface defects of the copper wire or the copper alloy wire are dissolved and removed, followed by a copper plating treatment or a copper alloy. A method for modifying the surface properties of a copper wire or a copper alloy wire (hereinafter referred to as copper wire) for the production of an ultrafine wire that is subjected to plating treatment (hereinafter referred to as copper plating treatment or the like), and obtaining an ultrafine wire having a conductor diameter of 20 μm or less. The scratches, cracks, copper powder stamps, and the like on the surface of the wire, which are surface defects, which have been a problem when trying to do so, can be removed by a relatively simple process. That is, surface defects such as surface scratches, cracks, copper powder stamps, etc. in copper wires having a wire diameter of about 0.1 to 1.5 mm are treated with electrolytic polishing (anodic dissolution), nitric acid aqueous solution, sulfuric acid and hydrogen peroxide. First, it is dissolved and removed with an acid solution such as a mixed solution of water, and further, a copper or copper alloy plating layer (hereinafter referred to as a copper plating layer) is formed on the surface thereof. It is excellent in the property and it can be made into the state without the defect by wire drawing. This is because the copper plating layer or the like formed by the plating process has no surface defects that are harmful during the wire drawing process, and thus contributes to the modification of the surface properties because it provides good wire drawing properties. For this reason, even if an ultrafine wire of 20 μm or less is manufactured by a subsequent wire drawing process, the occurrence of disconnection is extremely reduced. Further, since it is performed in a continuous process, it is possible to prevent contamination problems and trauma, and it can be performed in a relatively simple process.

  Further, the invention described in claim 2 is a preferable method in the surface property modification method for the copper wire or the like for manufacturing the ultrafine wire described above, and is divided into an electrolytic polishing treatment tank and a plating treatment tank by partition walls made of an insulating material. Each of which is filled with an electrolytic solution containing copper ions, and the electrode (cathode) connected to the negative side is connected to the electropolishing bath, and the positive side is connected to the plating bath In this state, the surface of the copper wire or the like is subjected to electrolytic polishing (anodic dissolution) treatment by continuously passing the copper wire or the like through the electrolytic polishing bath and then through the plating bath. Then, a surface property modification method for a copper wire or the like for manufacturing an ultrafine wire, in which a copper plating treatment or the like is performed next. As the copper wire 7, copper such as pure copper wire, tin-containing copper alloy wire (for example, 0.3 mass% Sn—Cu alloy wire), silver-containing copper alloy wire (for example, 1 mass% Ag—Cu alloy wire), etc. An alloy wire can be used, and the wire diameter is preferably about 0.1 to 1.5 mm.

  This will be described with reference to FIG. Reference numeral 1 denotes an outline of a contact-less power supply type surface property reforming apparatus used in a surface property modification method for copper wire or the like for manufacturing ultrafine wires according to the present invention, and is usually an electrical insulator such as vinyl chloride resin or FRP. Made of materials. Moreover, it is divided into an electropolishing treatment tank 3 and a plating treatment tank 4 by a partition wall 2 made of the same electrically insulating material as described above. The electrolytic polishing tank 3 and the plating tank 4 are filled with respective electrolytic solutions 5 and 5 '. Further, electrodes 6 and 6 ′ are arranged in the electrolytic polishing tank 3 and the plating tank 4, and the electrode (cathode) 6 in the electrolytic polishing tank 3 is on the negative side, and the electrode (anode) in the plating tank 4 is on the negative side. ) 6 'is connected to the plus side. The electrode 6 is made of copper, stainless steel or the like, and the anode-dissolved copper is deposited on the surface as metallic copper. On the other hand, the electrode 6 'is connected to an anode (anode), and copper eluted by energization is deposited on the surface of a copper wire or the like to form a plating layer. For this purpose, the electrode 6 'is mainly made of a phosphorus-containing copper alloy having excellent solubility, but oxygen-free copper or electrolytic copper can also be used. And the copper wire etc. 7 which modify the surface properties can be processed while moving sequentially from the electrolytic polishing bath 3 side to the plating bath 4 side.

  The electrolytic solutions 5 and 5 'may be any one containing copper ions. Specifically, an aqueous copper sulfate solution, an aqueous copper borofluoride solution, an aqueous copper pyrophosphate solution, or the like is used. Of these, an aqueous copper sulfate solution is preferred because of its excellent current efficiency and easy drainage treatment. In order to form a copper alloy plating layer, a water rinsing tank is provided between the electrolytic polishing tank 3 and the plating tank 4 to prevent the electrolytic solution from being brought in from the electrolytic polishing tank 3, and the plating tank If a copper alloy plating solution and an anode (anode) for copper alloy plating are arranged in 4 and the surface property modification treatment method of the present invention is carried out, a copper alloy plating layer can be formed on a copper wire or the like. Since the electrolytic solution contains copper ions in this way, the copper ions dissolved in the anode in the electrolytic polishing tank 3 and the plating tank 4 are deposited on the cathode. The balance is balanced, and the resistance value of the electrolytic solution hardly fluctuates, and a copper wire or the like for manufacturing an ultrafine wire can be obtained stably. In the above description, the electrolytic cell is divided into the electrolytic polishing tank 3 and the plating tank 4 by the partition wall 2, but the tanks 3 and 4 are independent from each other, and the copper wire 7 is continuous inside. It is good also as the tank which enabled it to pass.

By the above surface property modification method, the surface of the copper wire or the like 7 is first electropolished to remove surface defects such as surface scratches, cracks, and copper powder stamps. Then, a copper or copper alloy plating layer is formed on the copper wire or the like 7 whose surface has been subjected to electropolishing treatment. By using the surface property modification method in this way, the surface obtained is clean, so the adhesion of the plating layer is excellent, and the attached plating layer is excellent in workability, so that it can be processed as a wire rod for wire drawing. As a result, there is no surface defect that is harmful during the wire drawing process, and the wire has good wire drawing. For this reason, even if an ultrafine wire is manufactured by wire drawing processing, disconnection is very rare, and it is preferable as a copper wire or a copper alloy wire for manufacturing an ultrafine wire of 20 μm or less. In more detail, first, in the electropolishing treatment tank 3, the arranged electrode 6 becomes a cathode (cathode), and the copper wire or the like 7 whose surface properties are to be modified becomes an anode (anode), so that contactless electrolysis is performed. As a result of the treatment, copper is eluted from the surface of the copper wire or the like 7 and at the same time, surface defects such as scratches, cracks, and stamps of copper powder are dissolved and removed. Since the thickness of the surface defect is usually about several tens of μm, it is sufficient that this thickness can be removed. The conditions of the electropolishing process vary depending on the processing time, but practically the current density is 5 A / dm ² or more and the upper limit. Is usually performed up to about 100 A / dm ² .

Then, in the plating tank 4, electrolytic treatment is performed in which the copper wire or the like serves as a cathode (cathode), and a plated layer of copper or a copper alloy can be formed on the surface thereof. If the thickness of this plating layer is about several tens of μm, disconnection will not occur in the subsequent wire drawing. The current density in the plating tank is usually 10 A / dm ² or more. Under such conditions, the plating layer having the above-mentioned thickness can be formed by sufficiently adhering, and the deposited copper does not contain impurities, foreign matters, defects, etc. that cause disconnection in wire drawing. A copper surface can be formed. Thus, in both the electrolytic polishing tank 3 and the plating tank 4, the copper wire 7 for modifying the surface properties can be a contactless power supply surface property modifying method. . In the surface property modification treatment method of the present invention described above, the copper wire 7 is usually subjected to a removal treatment such as wire drawing oil before the electropolishing treatment, and water washing for removing the electrolyte solution after the plating treatment. Processing such as hot water washing, drying, etc. is performed.

  Furthermore, as described in claim 3, the present invention provides the same effect as described above even when the surface defects are dissolved and removed by a surface property modification method such as a copper wire for manufacturing an ultrafine wire, which is an acid dissolution treatment. can get. Since such a processing method can be performed by a relatively simple process, the cost of the apparatus is small and practical. This will be described with reference to FIG. In the present invention, the surface defects of the copper wire 7 and the like are dissolved and removed in an acid dissolution tank indicated by 8. That is, by passing through a tank filled with nitric acid aqueous solution, sulfuric acid and hydrogen peroxide solution mixture or ferric chloride aqueous solution etc., surface defects such as copper wire 7 scratches, cracks, copper powder stamps etc. To be removed. This is a portion corresponding to the electrolytic polishing tank 3 of FIG. Usually, a water washing tank 9 is provided after the acid dissolution tank 8. Then, the acid dissolution tank 8 dissolves and removes surface defects of the copper wires 7 for producing the fine wires by several tens of μm. In addition, the copper wire etc. 7 used here has an outer diameter of about 0.1 to 1.5 mm. And the water-washing tank 9 and the plating process tank 4 which has arrange | positioned electrode 6 'are arrange | positioned next. In the plating tank 4, a water-soluble electrolytic solution containing copper ions such as a copper sulfate aqueous solution, a copper borofluoride aqueous solution, or a copper pyrophosphate aqueous solution is used as the electrolytic solution 5 ′. Of these, an aqueous copper sulfate solution is preferred because of its excellent current efficiency and easy drainage treatment.

  The electrode 6 'is connected to the positive side, and the copper wire 7 is connected to the negative side by a contact type power supply member 10 such as a power supply roll to form a cathode. In such a state, the copper wire or the like 7 whose surface properties are modified is processed while moving in order from the acid dissolution tank 8 side to the plating treatment tank 4 side. What is necessary is just to form the thickness of a plating layer normally about several tens of micrometers. By adopting such a surface property modification method for copper wires for the production of ultrafine wires, surface defects such as scratches, cracks, and stamps of copper powder can be removed by acid dissolution with a relatively simple method, followed by plating. The layers are also formed in close contact with each other. This makes it possible to obtain a copper wire and the like preferable for producing an ultrafine wire of 20 μm or less, with extremely few occurrences of disconnection or the like during wire drawing. Further, since the surface property modification treatment is performed in a relatively simple continuous process, it is possible to prevent contamination problems and trauma, and is practical in terms of cost.

  The effects of the present invention were confirmed by experimental examples. A copper wire (pure copper wire) and a tin-copper alloy wire (Sn 0.3 mass% Cu) with an outer diameter of 0.18 mm treated under various conditions using the surface property reformer shown in FIG. 1 and FIG. Measures the rate of occurrence of disconnection (%) that occurs when a copper wire with the same outer diameter without any treatment (1.0 kg in length) is drawn with a diamond die to an outer diameter of 15 μm. And evaluated. The disconnection occurrence rate indicates a relative frequency as an occurrence rate with respect to a case where Experimental Examples 1 and 5 which are examples in which the surface property modification treatment is not performed is 100%. In addition, the conditions for modifying the surface properties are as follows.

In the case of the surface property modification treatment method using the apparatus of FIG. 1, a pure copper wire (purity 99.9%) having an outer diameter of 0.18 mm and a tin-copper alloy (Sn 0.3 mass% Cu alloy) An electrolytic polishing bath in which 250 g of copper sulfate and 70 g of sulfuric acid are dissolved in pure water and filled with a stainless steel electrode (connected to the negative side) is filled with the same solution as the electrolyte. The surface property modification treatment was performed by continuously passing through a plating treatment tank in which an electrode (connected to the plus side) of a phosphor copper alloy containing 05% by mass of phosphorus was disposed. The electrolytic polishing treatment conditions were: electrolyte stirring (approximately 2 m / sec pump stirring), electrolyte temperature of 50 ° C., wire current density of 20 A / dm ² , dipping time of 4 minutes and 30 seconds, wire surface The removal thickness of the layer is 20 μm. The plating treatment conditions were stirring of the plating solution (pump stirring of about 2 m / sec), the temperature of the plating solution was 50 ° C., the electrolytic current density was 40 A / dm ² , the immersion time was 2 minutes and 15 seconds, and the linear velocity was 1 m / second. min and 5 m / min, and copper plating thicknesses are 20 μm and 4 μm. (Experimental examples 2 and 3)

Further, in the case of the surface property modification treatment method using the apparatus of FIG. 2, a pure copper wire (purity 99.9%) having an outer diameter of 0.18 mm and a tin-copper alloy (Sn 0.3 mass% Cu alloy) are drawn. At a speed of 1 m / min, a 4.4 m long acid dissolution tank filled with a 40% by volume nitric acid aqueous solution, followed by a water washing tank, an electrolyte similar to the electrolyte used in FIG. The surface properties were reformed by continuously passing through a plating bath in which an electrode (connected to the plus side) of a phosphorous copper alloy containing bismuth was disposed. The acid dissolution treatment conditions are a liquid temperature (room temperature), and the removal thickness of the surface layer is 20 μm. The plating treatment conditions were: plating solution stirring (about 5 m / sec pump stirring), plating solution temperature of 50 ° C., electrolytic current density of 40 A / dm ² , immersion time of 2 minutes and 15 seconds, and copper plating thickness 20 μm. (Experimental examples 4 and 7) Further, for comparison, pure copper wire and tin-copper alloy wire (Sn 0.3 mass% Cu wire) when no electrolytic polishing treatment, acid dissolution removal treatment, and plating treatment are performed at all. It described as Experimental Example 1 and Experimental Example 5. The results are shown in Table 1.

As is apparent from Table 1, compared with the case where the surface property modification treatment of the present invention of Experimental Examples 1 and 5 is not performed, the copper subjected to the modification treatment of the surface properties described in Experimental Examples 2 to 4, 6 and 7 It was found that disconnection hardly occurred even when a wire was drawn to 15 μm using a wire or the like. That is, as in Experimental Example 2, a pure copper wire was used, the current density of the electrolytic polishing treatment bath using an aqueous copper sulfate solution was 20 A / dm ² , the current density of the plating bath was 40 A / dm ² , and the copper plating layer When the reforming process was performed with a thickness of 20 μm and a linear velocity of 1 m / min, the disconnection occurrence rate was almost 3%. In addition, when nitric acid dissolution treatment was performed instead of the electrolytic polishing treatment under the same conditions, the occurrence rate of disconnection was almost 4% as described in Experimental Example 4. In addition, as described in Experimental Examples 6 and 7, when an electropolishing treatment and a plating treatment, or a nitric acid aqueous solution dissolution treatment and a plating treatment were performed under the same conditions as in Experimental Examples 2 and 4 using a tin-copper alloy wire However, the occurrence rate of wire breakage due to wire drawing was about 4%, and almost no wire breakage occurred. It should be noted that pure copper wire was used as in Experimental Example 3, the current density of the electrolytic polishing treatment bath of copper sulfate aqueous solution was 20 A / dm ² , the current density of the plating bath was 40 A / dm ² , and the thickness of the copper plating layer Was 4 μm and the linear velocity was 5 m / min, the rate of occurrence of disconnection was 55%, and the reforming effect was small.

  According to the method for modifying the surface properties of copper wires and the like as described above, an ultrafine wire of 20 μm or less can be efficiently produced without being disconnected even by wire drawing, and used as an ultrafine wire for a small electronic device or the like. it can. The surface property modification treatment method is also relatively simple and practical at a low cost.

It is sectional drawing which shows the outline of the surface property modification processing apparatus of the non-contact electric power feeding system used for the surface property modification processing method of this invention. It is a schematic sectional drawing which shows another example of the surface property modification processing apparatus of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Surface property modification processing apparatus 2 Partition 3 Electropolishing processing tank 4 Plating processing tank 5, 5 'Electrolytic solution 6, 6' Electrode 7 Copper or copper alloy wire 8 Acid dissolution tank 9 Washing tank 10 Feeding member

Claims (3)

  A copper wire or a copper alloy wire for producing an extra fine wire, wherein the surface defect of the copper wire or the copper alloy wire is dissolved and removed, followed by a copper plating treatment or a copper alloy plating treatment. A method for modifying the surface properties of copper wire or copper alloy wire for wire production.   The method for modifying the surface properties of the copper wire or copper alloy wire for producing the ultrafine wire is divided into an electrolytic polishing treatment tank and a plating treatment tank by partition walls made of an insulating material, and each contains an electrolytic solution containing copper ions. The electrolytic polishing bath is provided with an electrode (cathode) connected to the negative side, and the plating bath is provided with an electrode (anode) connected to the positive side. The surface of the copper wire or copper alloy wire is electropolished by continuously passing the copper wire or copper alloy wire through the electrolytic polishing treatment tank and then the plating treatment tank in the state, and then the copper plating treatment or The method for modifying the surface properties of a copper wire or a copper alloy wire for producing an ultrafine wire according to claim 1, wherein a copper alloy plating treatment is performed.   The method for modifying the surface properties of a copper wire or a copper alloy wire for producing an ultrafine wire according to claim 1, wherein the dissolution and removal of the surface defects is an acid dissolution treatment.

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