JPH0343717Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a wire bonding device for connecting lead wires to a semiconductor chip.

Generally, the above-mentioned wire bonding apparatus is provided with a rotatable operating rod having a capillary, and by rotating the operating rod and pressing the capillary against the semiconductor chip with a predetermined pressure, the wire bonding apparatus can perform resistance welding, thermocompression bonding, or The lead wire is connected to the semiconductor chip by ultrasonic welding or the like. Therefore, in order to properly connect the lead wire, the displacement of the capillary, that is, the rotational drive of the operating rod, must be controlled with high precision in order to maintain the pressure contact between the capillary and the semiconductor chip at a predetermined pressure. There must be.

Conventionally, in wire bonding devices, a cam or a crank mechanism has been used as a means for rotationally displacing an operating rod. However, when using a cam, there are limits to the shape accuracy and surface processing accuracy of the cam itself, which not only makes it impossible to position the capillary with high precision, but also reduces the surface roughness and the formation accuracy of the cam itself. There were cases where the capillary was prone to vibrate along with the operating rod depending on the situation.

Furthermore, when a crank mechanism is used, one end of the crank rod must be rotatably connected to the drive source and the other end to the operating rod. The disadvantage is that the value decreases.

This idea was made based on the above circumstances,
The purpose is to provide a wire bonding device that can smoothly displace a capillary without vibration and with high positioning accuracy.

An embodiment of the present invention will be described below with reference to the drawings. In the figure, reference numeral 1 denotes a control motor as a drive source fixed to a base 2 by a mounting plate 3. A coupling 5 is fixed to the rotating shaft 4 of the control motor 1 with a screw 6. As shown in FIG. The coupling plate 7 is formed on one end of the coupling plate 7, and the coupling plate 7 is screwed onto the coupling plate 5 so that the eccentric shaft 9, which has a stopper 8 screwed onto the other end, is eccentric by a predetermined dimension with respect to the rotating shaft 4. 10 are connected to each other.

A first radial bearing 11 is provided at the center of the eccentric shaft 9, and a pair of second radial bearings 12 are provided on both sides of the first radial bearing 11. The second radial bearing 12 has a smaller outer diameter than the first radial bearing 11.

One end of a connecting body 23 is connected to the eccentric shaft 9. That is, this connecting body 23 is formed by sandwiching and fixing a band-shaped first member 23a and a second member 23b by a pair of combined bodies 25 such that the length thereof can be freely adjusted. Four screws 26 are arranged in a rectangular shape at one end of the first member 23a. These screws 2
A rectangular plate-shaped plate spring 27 is coupled to the portion of the first member 23a of No. 6 that protrudes from the lower surface side via a spacer 28 provided on the upper and lower surfaces thereof.

The outer ring 11a of the first radial bearing 11 is
The connecting body 23 is pressed against only the upper surface of the leaf spring 27.
is in a non-contact state with the lower surface of the first member 23a. Outer ring 1 of the pair of second radial bearings 12
2a is in pressure contact with the lower surface of the first member 23a, and is not in contact with the upper surface of the leaf spring 27. Therefore, one end of the connecting body 23 is connected to the first and second radial bearings 11 and 12 in response to the eccentric rotation of the eccentric shaft 9.
are connected so as to move in the vertical direction.

On the other hand, a support 18 is provided on the base 2 so as to be movable along the longitudinal direction of the connecting body 23 shown by the arrow in FIG. 1, and fixed at any position by means not shown.

An actuating body 20 having an ultrasonic oscillator 19 integrally attached to the support body 18 is rotatably held at a midway portion by a shaft 20a. A capillary 21 is attached to the tip of the ultrasonic oscillator 19.

Next, the operation of the above configuration will be explained. First, operate the control motor 1 and move the rotating shaft 4 with the arrow a
When the amount of eccentricity of the eccentric shaft 9 increases by rotating it in the direction shown, the first member 23a of the connecting body 23
One end portion is pushed up by the outer ring 12a of the second radial bearing 12, which rotates eccentrically together with the eccentric shaft 9. Thereby, the actuating body 20
It rotates counterclockwise as shown by the arrow in FIG. 1 using 0a as a fulcrum.

When the actuating body 20 rotates, the ultrasonic transducer 19 provided integrally with the actuating body 20 rotates, so that the capillary 21 provided at the tip of the actuating body 20 is displaced downward, and a predetermined amount is applied to the semiconductor chip (not shown). Since they are brought into contact with each other by pressure, a lead wire (not shown) passed through the capillary 21 is bonded.

The rotating shaft 4 of the control motor 1 stops near the rotational position where the amount of eccentricity of the eccentric shaft 9 is maximum.

On the other hand, when the rotating shaft 4 of the control motor 1 rotates in a direction opposite to the previous direction in which the amount of eccentricity of the eccentric shaft 9 decreases, the spring body 27 is pressed by the outer ring 11a of the first radial bearing 11. .

The spring body 27 is connected to one end of the first member 23a of the connecting body 23 via a screw 26 and a spacer 28. One end of this connecting body 23 is connected to the outer ring 12a of the second radial bearing 12 that rotates eccentrically.
is pressed down via the spring body 27 and the first radial bearing 11. Therefore, the actuating body 20 rotates clockwise to raise the capillary 21.

By the way, when the capillary 21 descends and is displaced to a predetermined position, the rotating shaft 4 of the control motor 1 rapidly stops and the rotation direction is changed. body 2
One end of 3 is the outer ring 12 of the second radial bearing 12
It tries to rotate in the upward direction away from a.

One end of the connecting body 23 is connected via a screw 26 and a spacer 28 to a spring body 27 which is disposed so as to sandwich the eccentric shaft 9 and is in pressure contact with the outer ring 11a of the first radial bearing 11. Therefore,
Since the inertial force of the actuating body 20 is absorbed by the elastic deformation of the spring body 27, the actuating body 20
rotates too much and the outer ring 1 of the second radial bearing 12
I rarely leave 2a.

That is, the connecting body 23 has its end connected to the spring body 2.
7 and in contact with the outer ring 12a of the rotatable second radial bearing 12, it smoothly responds to the eccentric rotation of the eccentric shaft 9.

Since it is easy to process the surface roughness and shape of the outer rings 11a and 12a of the first and second radial bearings 11 and 12 and the connecting body 23 with high precision,
These allow the actuating body 20, that is, the capillary 21, to be displaced smoothly and with high precision via the connecting body 23.

Since the connecting body 23 has the first member 23a and the second member 23b connected by the connecting plate 25, the length thereof can be adjusted freely. Therefore,
If the length of the connecting body 23 is changed and the support body 18 provided with the actuating body 20 is slid on the base 1,
The rotation angle of the actuating body 20, that is, the amount of displacement of the capillary 21 can be changed.

As described above, this invention provides one first radial bearing and a pair of second radial bearings on the rotating shaft that rotates eccentrically, and connects one end of the connecting body for rotationally displacing the capillary to the second radial bearing. A spring body is placed in contact with the outer circumferential surface of the first radial bearing, and is disposed on one end of the connecting body so as to sandwich the eccentric shaft with this one end, and is in contact with the outer circumferential surface of the first radial bearing. Connected by screws.

Therefore, the capillary can be made to respond smoothly to the eccentric rotation of the eccentric shaft. Furthermore, the surface roughness and shape of the radial bearing can be easily machined with high precision. Therefore, the capillary interlocked with each of the radial bearings can be displaced and positioned with high precision without causing vibration.

[Brief explanation of the drawing]

Figure 1 is a side view showing one embodiment of the present invention;
The figure is a partially sectional side view taken along the - line in FIG. 1. 1... Control motor (drive source), 4... Rotating shaft,
9... Eccentric shaft, 11... First radial bearing, 1
2... Second radial bearing, 20... Operating body, 2
3... Connecting body, 23a... First member, 23b...
...second member, 26...screw, 27...spring body.

Claims (1)

[Claims for Utility Model Registration] (1) A drive source, an eccentric shaft eccentrically connected to the rotating shaft of the drive source, a first radial bearing attached to the eccentric shaft, and the eccentric The first radial bearing is attached to the shaft with the first radial bearing sandwiched therebetween.
A pair of second radial bearings with a smaller outer diameter than the radial bearing of
a radial bearing, an elongated plate-shaped connecting body provided with one end in contact with the outer peripheral surface of the pair of second radial bearings so as not to contact the outer peripheral surface of the first radial bearing, and the connecting body. Two pairs of screws are arranged at one end so as to sandwich the eccentric shaft, and the lower ends of these screws are attached so as to contact the outer peripheral surface of the first radial bearing, and the connection is made through the screws by elastic force. a spring body that transmits the eccentric rotation of the eccentric shaft to the connecting body by pressing one end of the body against the outer circumferential surface of the second radial bearing; and a spring body that is connected to the other end of the connecting body and has a capillary at its tip. and an actuating body that is swingably provided so as to follow the movement of the connecting body. (2) The connecting body is characterized in that it consists of a first member and a second member that are divided in the longitudinal direction, and these first and second members are connected so that their length can be freely adjusted. A wire bonding apparatus according to claim 1 of the utility model registration claim.