JPS6112376B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a wire bonding apparatus for manufacturing semiconductor devices, and more particularly to a wire bonding apparatus capable of high-speed bonding.

Generally, a wire bonding apparatus is used to perform a wire bonding operation in which a wire such as a thin gold wire is used to connect a bonding pad on a semiconductor pellet to an external lead. In this wire bonding work, a tapered cylindrical body called a capillary that guides the wire and performs bonding is moved horizontally using a pulse motor etc. to a predetermined position for bonding, and after reaching the predetermined position, it is placed on the pellet. This is done by moving it vertically.

The vertical drive means for this capillary is as follows:
Conventionally, a cam drive mechanism has been used, an example of which is shown in FIG. That is, the bonding arm 1 has a fulcrum 2 at its center, and a capillary 3 is held at one end thereof. A cam follower 5 that moves periodically in the vertical direction in the figure following the cam 4 is in contact with the other end of the bonding arm 1. Following the vertical movement of the cam follower 5, the bonding arm 1 is pulled. It is swung around the fulcrum 2 by the tension spring 6. Note that the tension spring 7 has the function of ensuring the movement of the cam follower 5.

However, in the cam drive mechanism as described above,
Capillary 3 to increase bonding speed
When operated at high speed, the cam follower 5 and the bonding arm 1 themselves have considerable weight, so the cam 4 and the cam follower 5, or the cam follower 5 and the bonding arm 1 separate from each other due to inertia, and the bonding arm 1 moves as desired. The bonding process will not be performed properly and the specified bonding will not be possible.

As a method to solve the above technical problem, the spring constant of the tension springs 6 and 7 may be increased,
There are methods such as reducing the inertia of the cam follower 5 and bonding arm 1, or selecting the cam shape of the cam 4 to reduce its cam lift. However, even in these methods, it is necessary to limit the bonding speed in order to ensure that a predetermined bonding is performed.

The present invention has been made to eliminate the above-mentioned drawbacks, and its object is to provide a wire bonding apparatus capable of high-speed wire bonding.

The present invention will be specifically explained below using Examples.

FIG. 2 shows an example of the wire bonding apparatus of the present invention. In the following description, parts having the same functions or actions as those in FIG. 1 will be described with the same designation numbers.

In the figure, 1 is a bonding arm, 2 is a block rotatably attached to a rotation shaft 8 and allows the bonding arm 1 to swing, and 3 is a capillary. Reference numeral 6 denotes a tension spring provided at the other end of the bonding arm 1, which acts as a bonding load. That is, bonding is performed by the spring force of this tension spring 6.
Further, a protrusion 9 is provided on the side of the other end of the bonding arm 1 . Reference numeral 11 denotes a drive lever rotatably attached to the rotation shaft 17 at approximately the center thereof, and 15 is a force lever rotatably attached to the rotation shaft 14 at approximately the center thereof. They are arranged side by side with rotation plates 26 and 27 standing in parallel. 20 is a transmission lever whose one end is rotatably attached to a rotation shaft 21, and a chain line 23 is a cam rotationally driven by a rotation mechanism (not shown).

The transmission lever 20 has a cam follower 22 attached to its substantially central portion, and is arranged so that the cam follower 22 contacts the peripheral surface of the cam 23. Further, a tension spring 24 is attached above the tip of the transmission lever 20. Therefore, the rotation of the cam 23 causes the transmission lever 20 to move up and down about the rotation shaft 21 as a fulcrum.

One end of the drive lever 11 is connected to the end of the transmission lever 20 via a rod end 18, a connecting rod 25, and a rod end 19, and the other end is perpendicular to the protrusion 9 provided on the bonding arm 1. A projection 10 is provided. This protrusion 10 is placed above the protrusion 9 provided on the orthogonal bonding arm 1. Therefore, the protrusion 10 of this drive lever 11
The protrusion 9 of the bonding arm 1 is pressed against the lower surface of the bonding arm 1 from below by the tensile force of the tension spring 6.

With the above configuration, the movement of the transmission lever 20 which moves up and down due to the rotation of the cam 23 is transmitted to the drive lever, and the bonding arm 1 is caused to move up and down following the up and down movement of the drive lever 11.

The force lever 15 has a tension spring 16 below one end thereof, and the drive lever 11 at the other end.
A protrusion 12 is provided that is parallel to the protrusion 10 provided at the tip. This protrusion 12 is
The force of the tension spring 16 causes it to be pressed against the lower surface of the protrusion 9 provided on the bonding arm 1. Therefore, the bonding arm 1 is in a state as if it were held between the drive lever 11 and the force lever 15. This forced lever 1515 is for further promoting the ability of the bonding arm 1 to follow the movement of the drive lever 11. In particular, this is intended to encourage the upward movement of the protrusion 10 in the drive lever 11 by forcibly pushing it up from below. Also, this forced lever 1
A stopper 13 is provided near the protrusion 12 of 5, which acts only when the force lever 15 moves upward. This stopper 13 is connected to the connecting plate 28.
It is attached to the fixed plate 26 via. This stopper 13 is for stopping the forced operation of the forcing lever 15 at the start of bonding.
That is, the force lever 15 is moved upward by the tension spring 16 and hits the stopper 13, so that it is prevented from moving any further. By providing such a stopper 13, proper bonding can be performed purely by the bonding load (tension spring 6) without applying any force to the bonding arm 1 during bonding. Therefore, stopper 1
3 must be installed in a position that can achieve this purpose.

The operation of the wire bonding apparatus having the above configuration is as follows. In the following description, arrows shown by solid lines in the figures indicate operations during bonding, and arrows indicated by broken lines indicate operations during non-bonding.

First, when bonding work is not being performed, the short diameter portion of the cam 23 is in contact with the cam follower 22, and therefore the tip of the transmission lever 20 is fixed to the lowermost portion. In such a state, drive lever 1
1. The force lever 15 and the bonding arm 1 are maintained in a substantially horizontal state, and the tip of the capillary 3 is separated from the material to be bonded (not shown). At this time, the protrusion 9 of the bonding arm 1 is held in a substantially horizontal state by the protrusion 10 of the drive lever 1 and the protrusion 12 of the force lever 15. Further, the upper end of the force lever 15 does not come into contact with the stopper 13 and is spaced apart from it at a predetermined distance.

Next, during the bonding work, the cam 23 may be rotated so that its long diameter portion comes into contact with the cam follower 22. As a result, the transmission lever 20
The tip of the drive lever 11 moves downward, and along with this movement, the protrusion 10 of the drive lever 11 moves upward. Therefore, the protrusion 9 of the bonding arm 1, which has been pressed down by the protrusion 10, springs upward under the pressure of the tension spring 6. At this time, the protrusion 12 of the force lever 15, which was pressing down the protrusion 9 of the bonding arm 1 from below, acts to promote the springing movement of the protrusion 9 due to the pressure of the tension spring 16. This further promotes the ability of the bonding arm 1 to follow the upward movement of the drive lever 11. and,
When the force lever 15 hits the stopper 13, the foregoing force of the force lever 15 is no longer applied. Therefore, from now on, bonding will be performed only by the predetermined tensile force of the tension spring 6, that is, by the bonding load.

After the bonding is completed, the cam 23 is rotated so that its short diameter part comes into contact with the cam follower 22, and then the cam 23 returns to the initial state through the opposite movement path (as indicated by the broken line arrow) to the movement during bonding. return.

According to the wire bonding apparatus described above, the ability of the bonding arm 1 to follow the movement of the drive lever 11 at the start of bonding is ensured by the force lever 15 without depending on the spring force of the tension spring 6. Therefore, as before,
There is no possibility that the followability between the vertical movement mechanism and the bonding arm is deteriorated due to inertia of the bonding arm or the like. Therefore, the speed of the vertical movement mechanism can be increased, and a high-speed wire bonding device can be obtained.

In addition, the force of the force lever 15 is not applied at the start of bonding, but a stopper 13 is provided and the force is released by hitting the stopper 13, and bonding is performed purely with the bonding load, so that proper bonding can be achieved. It can be performed.

Furthermore, since the conventional device can be improved by adding only a few parts to the conventional device, it is also highly economical.

The present invention can be widely used as a wire bonding device.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing an example of a conventional cam drive mechanism, and FIG. 2 is a perspective view of essential parts of an example of a wire bonding apparatus according to the present invention. 1...Bonding arm, 2...Block,
3...Capillary, 4,23...Cam, 5,22
... Cam follower, 6, 7, 16, 24 ... Tension spring, 8, 14, 17, 21 ... Rotation shaft,
9, 10, 12...protrusion, 11...drive lever,
13...stopper, 15...forced lever, 18,
19... Rod end, 20... Transmission lever, 2
5... Connecting rod, 26, 27... Fixed plate, 28...
Connecting plate.

Claims (1)

[Claims] 1. A bonding arm that is arranged substantially flat on the block, is swingably supported, and has a cylindrical capillary that holds a wire at its tip, and the bonding arm is swung to move the capillary up and down. In the wire bonding apparatus, the vertical movement mechanism is configured to move up and down by a tension spring attached to the bonding arm section so as to apply a bonding load by a tension force, and a cam. A drive lever that is driven and whose tip is placed on the upper surface of the end of the bonding arm, and a drive lever that is disposed below the bonding arm and is configured to apply a forcing force to press the bonding arm against the lower surface of the drive lever. 1. A wire bonding apparatus comprising a forcible lever, the forcible lever being configured to release the forcible force when bonding is started.