JPS6220692B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a capillary vertical movement mechanism for vertically moving a capillary in a wire bonding apparatus.

Conventionally, as such a capillary vertical movement mechanism, those shown in Japanese Patent Application Laid-Open Nos. 54-154273 and 55-24403 are known. In this structure, the bonding arm holding the capillary is rotatably held by a vertically moving block, and this vertically moving block is slid up and down by a female screw block that is moved up and down by a motor. When the capillary hits the bonding surface, the height of the bonding surface is detected by a contact point or a microphone, and the motor rotates a little further so that the capillary remains in contact with the bonding surface and the vertical movement block further lowers and stops. In this way, the bonding arm is rotatably supported by the vertically movable block and moves up and down together with the vertically movable block, so the moment when the capillary hits the bonding surface and the moment when the vertically movable block further descends and stops are different. Misalignment occurs in the support shaft, which is the center of rotation of the bonding arm. As a result, the capillary is slightly misaligned, resulting in wire breakage, etc., which has a negative effect on bondability.

The present invention was made in view of the above-mentioned drawbacks of the prior art, and it is an object of the present invention to provide a capillary vertical movement mechanism that does not cause displacement of the capillary.

Hereinafter, the present invention will be explained with reference to illustrated embodiments.

FIG. 1 is a partially sectional side view showing an embodiment of the apparatus according to the present invention, and FIG. 2 is a sectional view taken along the line 2--2 in FIG. A bonding arm 11 holding a capillary 10 at one end is rotatably attached to a support shaft 1 via a bearing 14 to a head frame 13 fixed to an XY feeder 12 that moves in the XY direction.
It is fixed at 5. A cylindrical portion 13a concentric with the support shaft 15 projects inward from the head frame 13, and a drive block 17 is rotatably mounted via a bearing 16. The driving block 17 includes an insulating block 19 holding a contact rod 18.
is fixed, and the bonding arm 11 is attached to the support shaft 15.
The contact rod 18 is biased counterclockwise by a spring 22 applied to the hook 20 of the drive block 17 and the hook 21 of the drive block 17. Further, a clamp arm 24 holding a clamper 23 is fixed to the drive block 17.

A rotary encoder 3 is installed in the head frame 13.
0 is fixed, and the output shaft of this motor 31 has a male screw 3 that is rotatably supported on the head frame 13 via a bearing 32 at one end.
3 and joint 34. A female thread block 35 is screwed into the male thread 33,
A bearing 37 attached to a pin 36 fixed to the female thread block 35 is slidably fitted into a vertical groove 13b provided in the head frame 13 so that the female thread block 35 can move vertically but not rotate. There is. Further, a pin 39 to which a bearing 38 is attached is fixed to the female thread block 35, and the bearing 38 is held between two connecting pins 41 and 42 fixed to a drive arm 40 fixed to the drive block 17. There is.

Further, a spool lever 50 is attached to the head frame 13.
is fixed, and a spool 52 around which a wire 51 is wound is attached to the end of the spool lever 50. The wire 51 wound around the spool 52 is inserted into the capillary 10 through the guide pipe 53 and the clamper 23. Further, the lead frame 61 with pellets 60 attached thereto is guided and transported by a frame feeder 62.

Next, the operation of this device having such a configuration will be explained. FIG. 1 shows the moment when the capillary 10 hits the bonding surface, but before wire connection, the capillary 10 is above the bonding surface, and the tip of the wire 51 protrudes from the tip of the capillary 10. Therefore, when the head frame 13 is moved on a plane by the XY feeder 12 and the capillary 10 is positioned above the first bond point, the motor 31 is rotated. The rotation of the motor 31 causes the female screw block 35 to move upward in the direction of arrow A. Since the drive arm 40 is fixed to the drive block 17, when the female screw block 35 moves upward in the direction of arrow A, the drive block 17 connects the head frame 13 via the bearing 38, the connecting pins 41 and 42, and the drive arm 40. It rotates in the direction of arrow B around the cylindrical portion 13a, and the clamper 23 attached to the contact rod 18 and the clamp arm 24 descends. Contact rod 1
8 descends, the bonding arm 11 rotates in the direction B around the support shaft 15 while being in pressure contact with the contact rod 18 due to the biasing force of the spring 22, and the capillary 1
0 goes down. As shown in FIG. 1, the moment the capillary 10 hits the bonding surface, the contact rod 18 is slightly separated from the bonding arm 11, and as a result, the bonding arm 11 and the contact rod 18 are no longer electrically conductive, so the height of the bonding surface is is detected. From this state, the motor 31 rotates slightly and then stops. Then, the wire 51 is bonded to the first bonding point using the capillary 10.

After the first bonding is completed, the motor 31 rotates in the opposite direction to the above, and the capillary 10 is raised by the reverse operation. This amount of increase is determined by the distance (wire length) to the second point. Subsequently, in the same manner as described above, the capillary 10 is moved in a plane by the XY feeder 12 and positioned above the second bonding point. Next, the motor 31 rotates, and the capillary 10 descends and presses against the second bonding point, completing the wire connection work. Then, when moving on to the next connection operation, the capillary 10 rises, but at this time the clamper 23 closes and cuts the wire 51. Here, the vertical amounts of the capillary 10 and the clamper 23, ie, the amount of rotation of the motor 31, are measured and controlled by the rotary encoder 30.

In this way, the bonding arm 11 is swingably supported by the head frame 13, and is configured to be swung by the drive block 17, which is swung by the internally threaded block 35 that is movable up and down. Even if the drive block 17 moves further than the state in which the capillary 10 is in contact with the bonding surface, the support shaft 15 that holds the bonding arm 11 does not move, and the capillary 10 does not slip, improving bondability.

In the above embodiment, the contact rod 18 integrated with the drive block 17 was brought into pressure contact with the lower surface of the bonding arm 11.
is extended to the other side of the support shaft 15, and the contact rod 18 is disposed on the upper surface side of this extended portion, and the bonding arm 1
The upper surface of the extension part 1 may be brought into pressure contact with the contact rod 18. Further, the drive block 17 is not limited to swinging, but may be configured to be vertically movable. Further, the height of the bonding surface may be detected by an optical detection method using a photo sensor or a sonic detection method using a microphone. Further, the vertical amount of the capillary 10 may be measured by a linear encoder or the like instead of the rotary encoder 30.

As is clear from the above description, according to the capillary vertical movement mechanism of the present invention, the capillary does not slip, so bondability is improved.

[Brief explanation of the drawing]

FIG. 1 is a partially sectional side view showing an embodiment of a capillary vertical movement mechanism according to the present invention, and FIG. 2 is a sectional view taken along line 2-2 in FIG. 10... Capillary, 11... Bonding arm, 13... Head frame, 15... Support shaft, 17... Drive block, 30... Rotary encoder, 31... Motor, 33... Male thread, 35... Female thread block, 4
0... Drive arm, 51... Wire.

Claims (1)

[Claims] 1. A vertically movable female screw block constituting a drive unit for vertically moving a capillary through which a wire is inserted, a male screw that is screwed into this female screw block and rotates, and a male screw fixed to a head frame that is movable in plane in the X and Y directions. The capillary vertical movement mechanism includes a motor that rotationally drives the capillary, and an encoder that controls the amount of rotation of the motor. A capillary for vertical movement, which is provided with a driving member extending on the surface of the bonding arm so as to prevent the bonding arm from moving in the downward direction, supported by the head frame so as to be swingable or vertically movable, and swingable or vertically movable by the female thread block. mechanism.