JPH0412402A - Extremely thin conductor and extremely thin enamel wire - Google Patents

Abstract

PURPOSE:To obtain the subject conductor and wire having low conductive resistance and performing transmission of high quality by Au plating a oxygen-free conductor which is made by adding fixed amount of Ag to Cu having purity not less than 99.99%. CONSTITUTION:This extremely thin conductor 1 consist of a conductor body 2 of Cu alloy made in a manner wherein Ag of 0.03 to 0.5wt.% is added to oxygen-free copper of high purity of Cu having purity not less than 99.99% and an Au plating layer 3 having the thickness 1 to 4mum is provided for covering the periphery of this conductor part 2. The conductor part 2 of this extremely thin conductive wire 1 is extremely thinned and desirably has a diameter not exceeding 4.0mum in parallel to match the miniaturization and weight reduction of magnetic heads. For impurities of the conductor part 2, magnetic elements such as Fe, Ni, Co are reduced to the minimum, that is, not exceeding 10ppm. Thereby, signal transmission having low conductor resistance and high quality can be performed. Since a small amount of Ag is added, breaking strength is increased so that breaking of a wire at the time of manufacture is scarce, further due to applied Au plating, bonding can be performed with good adhesiveness.

Description

[Detailed Description of the Invention] "Industrial Application Field" The present invention relates to a conductor that transmits high-quality signals, and in particular,
The present invention relates to an ultrafine conductor and an ultrafine enameled wire used in the coil of a magnetic head for continuous magnetic recording.

Conventional technology: Conventionally, enameled wires used in coils for magnetic heads of magnetic disk drives in computers have a structure in which an insulating layer is provided on a conductor portion made of general electrolytic copper or oxygen-free copper. used L). Here, the conductor portion is used having a diameter of about 50 to 55 μm, and the insulating layer is made of polyurethane resin and having a thickness of about 3 to 5 μm. Mar 2,
Especially in the case of conductors for continuous signal transmission, high-quality signal transmission is required and the conductivity of the conductor part must be sufficiently high, so high-purity Cu is used for the conductor part. Things are also being done.

``Problem to be solved by the invention'' However, with the recent miniaturization of magnetic disk drives, there has been a demand for miniaturization of the magnetic head itself.
Enameled wires for magnetic heads are also required to be made extremely fine.

As for the specific size, a diameter of about 20 to 30 μm is required, compared to the current conductor diameter of about 50 μm.

However, when the conductor diameter is increased from 50 μm to 30 μm, there is a problem that the tensile strength of the conductor decreases.

Here, for example, it is known that when the conductor diameter is changed from 50 μm to 30 μm, the tensile strength decreases to less than half.

Therefore, a problem has arisen in which the conductor becomes easily disconnected during processing steps such as wire drawing, plating, insulation coating, and connection to a magnetic head, which did not pose a problem with conventional wire diameters.

The method of winding enameled wire for magnetic heads is shifting from the conventional low-speed manual winding under a microscope to high-speed winding using automatic winding machines, so the conductor diameter has become smaller as mentioned above. In such a case, during the winding process using an automatic winding machine, the enamelled wire is stretched abnormally, resulting in an increase in conductor resistance and, in some cases, wire breakage. Furthermore, when the diameter of the conductor is reduced, there is a problem that the end of the enameled wire is broken during the process of routing and bonding the end of the enameled wire during assembly of the magnetic head.

The present invention has been made to solve the above problems, and has high breaking strength, reduces the risk of wire breakage in the manufacturing process, and can perform high-quality signal transmission.
The purpose of the present invention is to provide an ultrafine conductor and an ultrafine enameled wire that are easy to bond.

"Means for solving the problem" In order to solve the problem, the invention described in claim 1 has the following features:
0.03-0.5% by weight in Cu with purity 99.99% or more
The conductor part is made of oxygen-free copper added with Ag, and the conductor part is coated with a gold plating layer.

In order to solve the above problem, the invention described in claim 2 has the following features:
The gold plating layer according to claim 1 has a thickness of 1 to 4 μm.

The invention described in claim 3 is obtained by applying an insulating coating to the conductor according to claim 1 or claim 2.

Since the conductor portion is made of a high-purity Cu alloy containing Ag, conductor resistance is low and high-quality signal transmission is achieved. A
Since the content of g is limited to a specific amount, the effect of improving the conductor strength is sufficiently exhibited, and at the same time, the increase in cost due to the addition of Ag can be suppressed. Furthermore, since the gold plating layer is coated with a special thickness, an appropriate adhesion force can be obtained during bonding, and at the same time, an increase in cost due to the formation of the gold plating layer can be suppressed.

The present invention will be explained in more detail below.

FIG. 1 shows an embodiment of the ultrafine conductor of the present invention. The ultrafine conductor l of this example is made of high-purity oxygen-free copper with a purity of 99.99% or more and 0.03 to 0.5% by weight. It consists of a conductor part 2 made of a Cu alloy with added Ag, and a gold plating layer 3 with a thickness of 1 to 4 μm provided to cover the outer peripheral surface of the conductor part 2.

The diameter of the conductor portion 2 is 40 μm because the diameter of the conductor portion 2 is made ultra-thin in accordance with the miniaturization and weight reduction of magnetic heads to which the ultra-fine conductor l is applied.
It is preferable that it is below m. Further, since the ultrafine conductor 1 is used in a magnetic device such as a magnetic head, magnetic elements such as Fe, Ni, and Co should be avoided as much as possible as impurities contained in the conductor portion 2. Therefore, it is preferable that the content of the magnetic element is 10 ppm or less.

The reason why the purity of the oxygen-free copper in the Cu alloy constituting the conductor part 2 is set to 9999% or more is that if the purity is less than that, the conductor resistance will increase, which may impede high-quality transmission, or the softening temperature will rise. This is because it causes a problem. In addition, the oxygen content of oxygen-free copper is 30 ppm or less by weight, and 3
If it exceeds 0 ppm, oxides are generated, so
Wires tend to break when drawing them to ultra-thin diameters. The reason why the amount of Ag added is 0.03 to 0.05% by weight is not preferable because if it is less than 0.03% by weight, there is no effect of improving the tensile strength, and if it exceeds 0.5% by weight, the conductor resistance increases and the cost increases. The reason why the thickness of the gold plating layer 3 is set to 1 to 4 μm is that a thickness of less than 1 μm is undesirable because the adhesive strength will be low or the adhesive strength will vary when bonding to a magnetic head. Exceeding this is not preferable because it increases the cost.

When manufacturing the ultra-fine conductor l having the structure shown in FIG. 1, the conductor portion 2 can be obtained by, for example, a normal wire drawing method from a Cu alloy ingot having the above composition, and a gold plating layer 3 is formed. For example, electroplating may be used.

FIG. 2 shows an embodiment of the ultra-fine enameled wire of the present invention. The ultra-fine enameled wire 5 of this example has an insulating coating layer 6 formed on the outer peripheral surface of an ultra-fine conductor l having the structure shown in FIG. It is what it is.

Examples of the material constituting the insulating coating layer 6 include polyurethane, polyester, polyamide, polyimide, polyamideimide, polyesterimide, polyvinyl butyral, and epoxy. Note that when soldering is performed in the process of processing the ultrafine enameled wire 5, it is preferable to select polyurethane from among the above-mentioned materials.

Of course, the polyurethane can be colored if necessary.

Incidentally, in the embodiments shown in FIGS. 1 and 2, the cross-sectional shape of the conductor portion 2 is round, but the cross-sectional shape of the conductor portion 2 may be polygonal, elliptical, or irregularly shaped. Of course, the cross-sectional shape of the board may also be used.

"Example" Oxygen-free copper with purity of 99.97% and purity of 9999% was prepared, Ag was added in various proportions to these oxygen-free copper, and multiple ultrafine conductors with conductor diameters of 40 μm and 20 μm were formed. After manufacturing and forming gold plating layers of various thicknesses on these, polyurethane paint is applied and baked to a thickness of 2.
A plurality of ultrafine enameled wire samples were obtained by forming an 85 μm insulating layer.

The conductor resistance and tensile strength of each of the ultrafine enameled wire samples produced as described above were measured. In addition, some samples were bonded using an ultrasonic ponoder, and the adhesive properties were evaluated based on the results. These measurement results and evaluation results are shown in Table 1 below.

From the results shown in Table 1, it can be seen that samples No. 1 and No. 8 of the ultrafine enamelled wire of the present invention have lower conductor resistance, higher tensile strength, and better adhesion than samples No. 9 to No. 3 of the comparative example. found.

Effects of the Invention As explained above, the present invention has a conductor part made of a 99.99% pure Cu alloy containing a special amount of Ag, so the conductor resistance is low and high quality signals can be obtained. It has the feature of being able to transmit data. Furthermore, since 0.03 to 0.5% by weight of Ag is added to the conductor portion, the breaking strength is increased and wire breakage is reduced in each manufacturing process. Furthermore, since the conductor portion is coated with a gold plating layer, bonding during connection can be performed extremely easily with good adhesiveness.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an embodiment of the ultrafine conductor of the present invention, and FIG. 2 is a sectional view showing an embodiment of the ultrafine enameled wire of the present invention. l... Ultrafine conductor, 2... Conductor part, 3... Gold plating layer, 5
...Extra-fine enameled wire, 6...Insulating coating layer.

Claims (3)

[Claims] (1) 0.03 to 0.5 for Cu with purity of 99.99% or more
An ultra-fine conductor comprising a conductor part made of oxygen-free copper added with % by weight of Ag, and a gold plating layer covering the conductor part. (2) The thickness of the gold plating layer according to claim 1 is 1 to 4 μm.
An ultrafine conductor characterized by: (3) An ultrafine enameled wire obtained by applying an insulating coating to the conductor according to claim 1 or 2.