JPH07252540A - Manufacture of bonding wire and manufacturing device therefor - Google Patents

Abstract

PURPOSE:To provide a method and a device for manufacturing a bonding wire by executing heat treatment by conducting the electricity to the wire in order to adjust the mechanical property of the bonding wire. CONSTITUTION:In this manufacturing method of the bonding wire, a heat treatment for changing the required mechanical properties is executed by paying attention to the generating heat in the inner part of the wire by conducting a little current to the bonding wire. This manufacturing device of the bonding wire by heating with the electric power conduction is provided with a send-out means 3 for enabling send-out of the wire, a tensioner 4 for enabling control of the wire tension, electrodes 1, 2 arranged with respective angles from the send-out direction so that the sent out wire has the contacting parts, a constant current or a constant voltage power source 6 so as to be possible to conduct the electricity to the electrodes and a winding means 5 for enabling winding of the wire already undergone the heat treatment.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bonding wire manufacturing method for adjusting mechanical properties of a bonding wire by heat treatment, and a manufacturing apparatus therefor.

[0002]

2. Description of the Related Art In a conventional bonding wire manufacturing process, after drawing a wire to a final wire diameter, in order to adjust mechanical properties defined by a standard and to remove curl generated during wire drawing, Heat treatment using a tubular finish annealing furnace is performed. For example, in the case of a gold wire having a diameter of 30 μm, the temperature of the furnace is set to a high temperature of 400 ° C. or higher,
A tubular furnace having a length of about 1 m is used, and the wire is continuously passed through the furnace to change the mechanical characteristics. This heat treatment method requires a large-scale apparatus and a wire diameter of about 20 μm to 50 μm.
When handling a bonding wire of μm, workability is not good and work efficiency is poor. Further, in the heat treatment at 500 ° C. or higher, the wire is softened and broken during the work of passing the wire through the furnace tube, and it is impossible to handle. Further, in the tubular furnace, since the inside of the furnace is the atmosphere, it is easily affected by the outside air, and it is difficult to stably maintain the heat treatment temperature at a constant temperature. Further, the conventional furnace has a large-scale device and a large capacity, and it takes time to start up or change the temperature, and a large amount of electric power is required to keep the temperature high, resulting in high manufacturing cost.

On the other hand, the electric heating method may be used when a conventional copper wire is drawn and the diameter of the wire is large during the drawing. This is because processing strain is removed by heat treatment during wire drawing, that is, the wire is softened once,
This is done in order to prevent wire breakage caused by work hardening in the subsequent wire drawing step and to facilitate wire drawing, and not to adjust product characteristics.

[0004]

As described above, the heat treatment using the conventional tubular furnace has problems in temperature stability, work efficiency, and manufacturing cost. In view of the above, the present invention is capable of controlling product characteristics, performing heat treatment stably and efficiently in succession with other processes, and performing the heat treatment with a device that is smaller than a conventional large-capacity device. An object of the present invention is to provide a bonding wire manufacturing method and a manufacturing apparatus for the bonding wire, which increase efficiency and reduce manufacturing cost.

[0005]

The present invention will be described in detail below. In the present invention, since the final wire diameter of the bonding wire is very small, it is possible to change the mechanical characteristics of the wire, that is, the breaking strength and elongation during the tensile test of the wire, by resistance heating by passing a minute current. This is because the wire is brought into contact with the two electrodes to carry out electric heating.

The present invention will be described below with reference to the drawings. First, as shown in FIG. 1, the main components of this apparatus are electrodes 1 and 2, a wire feeding machine 3, a tensioner 4, a wire winding machine 5, a constant current or constant voltage power source 6, a motor 7, Motor speed controller 8
It has and. Next, as shown in FIG.
The tension can be controlled by being fed from the feeding machine 3 and passing through the tensioner 4. In order to prevent the wire from becoming thin and easy to break, it is preferable that the tensioner controls the tension at a low place.

Furthermore, the electrodes 1 and 2 arranged so as to form an angle with the feeding direction are brought into contact with each other so as to have a contact portion,
It is wired to the winder 5. This allows a current to flow between the electrodes 1 and 2 while maintaining a constant tension. Depending on the product wire diameter, etc.
By adjusting the voltage or current of the power supply 5,
A voltage of 0 to 60 V is applied between and. The power supply is capable of applying a constant voltage or flowing a constant current.

Further, in order to stabilize the mechanical characteristics of the wire, it is necessary to control the current with good control. The tensioner is controlled so as to keep the wire in contact with the electrodes 1 and 2 at all times. The electrode is, for example, of a roller type so as to be in continuous contact with the electrode, and the wire is bent so that the wire has a contact portion at the electrode portion, and the wire is adjusted so that a constant current always flows. Also, it is preferable to minimize the vibration caused by the operation of the motor.

Further, the wire is thin and the electrode is of a rotating type in order to prevent damage at the contact portion, and the electrode is controlled so as to rotate in synchronization with the feeding and winding of the wire to keep the peripheral speed of each rotating contact portion constant. It is equipped with a control device. Further, by adjusting the rotation speed of the motor 7 by the controller 8, the energization heating time, that is, the heat treatment time is adjusted. The rotation speed is variable from 0 to 100 r / min depending on the wire diameter and the like.

In the present invention, the mechanical properties required for the wire can be changed by changing the amount of current by changing the applied voltage or by adjusting the heat treatment speed by adjusting the number of rotations of the motor 7. It will be possible. Furthermore, in order to keep the temperature constant and suppress variations in product characteristics, the energization heating between the electrodes 1 and 2 may be performed in cooling water. Further, in order to make the electrodes resistant to rust and to enhance the conductivity, it is preferable to perform plating with a noble metal such as gold plating or Cr plating having high corrosion resistance.

[0011]

According to the present invention configured as described above, the heat treatment for adjusting the mechanical properties of the wire can be easily performed with a device smaller than the conventional tubular furnace, and the heat treatment can be performed continuously with other steps. It is possible to reduce the cost and improve the work efficiency.

[0012]

Example A gold wire having a strength of 32 gf and an elongation of 30 .mu.m and a wire diameter of 30 .mu.m was brought into contact with an electrode plated with gold at intervals of 50 cm and drawn out at the speed shown in Table 1. The electrode used was a rotating type and was rotated in synchronization with the wire feeding speed. At this time, when a voltage was applied between the electrodes, wire characteristic values (strength / elongation) as shown in Table 1 were obtained.

[0013]

[Table 1]

From this result, it is clear that the electric heating is effective in changing the mechanical properties of the wire. Further, it has been clarified that the heat-treated wire has the curl removed, and the curl can also be removed by electric heating. In addition, when the surface of the wire was observed, it was found that there was no surface scratch, and the generation of the wire scratch could be prevented by making the electrode a rotary type and synchronizing it with the wire feeding machine.

[0015]

As described above, according to the present invention,
Since the electric heating method is used as a heat treatment method for adjusting the mechanical properties of the wire drawn to the product wire diameter, temperature control can be performed more stably and the heat treatment apparatus can be downsized as compared with the heat treatment method using a tubular furnace. The manufacturing cost can be reduced. In addition, by adding electrodes to the wire drawing machine and rewinding machine, it is possible to easily carry out the process continuously with other processes, resulting in higher work efficiency, a significant reduction in mass production time, and cost reduction. It is possible to reduce.

[Brief description of drawings]

FIG. 1 is a schematic plan view showing the configuration of the entire apparatus in the present invention.

FIG. 2 is a schematic diagram showing an electric heating operation of a wire according to the present invention.

[Explanation of symbols] 1 electrode 2 electrode 3 wire feeding machine 4 tensioner 5 wire winding machine 6 power supply 7 motor 8 motor speed controller

Claims (2)

[Claims] 1. A heat treatment for changing required mechanical properties is performed by drawing a bonding wire to a product wire diameter and then generating heat inside the wire by passing a minute current through the bonding wire. Bonding wire manufacturing method. 2. A feeding means capable of feeding the wire, a tensioner capable of controlling the wire tension, and an electrode arranged so as to have an angle with respect to the feeding direction so that the fed wire has a contact portion. An apparatus for producing a bonding wire by energization heating, comprising: a constant current or constant voltage power source capable of energizing the electrode, and a winding means capable of winding a heat-treated wire.