JPH0521879Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention relates to a wire bonding device used in manufacturing semiconductor devices, and particularly to a wire feeding device thereof.

[Conventional technology]

The second example of the conventionally used wire feeding device is
As shown in the figure.

Reference numeral 1 denotes a spool for feeding out wire, which is equipped with a motor 2 as a rotational drive source and is supported by a bonding head 3. 4 is a clamp, 5 is a capillary or wedge (hereinafter referred to as a bonding tool) attached to the bonding arm 6, 7 is a guide,
8 is a wire payout amount control device provided in the wire path from the spool 1 to the guide 7, which blows air onto the wire and causes the wire to pay out from the spool 1 depending on the amount of deflection; The sensor 10 detects the maximum deflection state of the wire, and the sensor 11 detects the minimum deflection state of the wire.When the sensor 11 detects the wire, the motor 2 is turned on, and when the sensor 10 detects the wire, the motor 2 is turned on. The distance between the sensors 10 and 11 is set such that bonding can be performed multiple times with one feeding of the spool 1, for example.

[Problem that the invention attempts to solve]

For example, when connecting a pad of an IC chip as a first bonding part and a lead of a board as a second bonding part with a wire, after the first bonding to the pad is completed, the bonding tool 5 is operated with the clamp 4 open. Ascent, horizontal movement,
The pad is lowered and moved to the position of the lead where the second bonding is to be performed, and the pad and the lead are connected using a loop-shaped wire. It depends on the tension of the wire when 5 is moving to the second bonding part. If the tension is too large, the wire may break, and if the tension is too small, the initial loop shape will not be formed at the bonding part and sag. or curling may occur.

The tension of the wire at this time can be adjusted by the air supply conditions of the feed amount control device 8 and the distance of the wire from the air supply port.

Therefore, bonding is performed by setting the air supply conditions constant so that the wire has a tension (referred to as the optimal tension) that provides the optimal loop shape when the wire runs through the position shown by the solid line in Figure 2. When the wire is running at the position indicated by the two-dot chain line in Fig. 2, the tension is greater than the optimum tension because it is close to the air outlet 9. When the vehicle is running, the tension is smaller than the optimum tension because the vehicle is far from the air outlet 9. Therefore, since the tension of the supplied wire varies widely, it is difficult to obtain the initial loop shape in all bondings.

As a means to eliminate this problem, it is conceivable to reduce the number of consecutive bonding operations performed in one unwinding of the spool 1 and to reduce the displacement of the wire running position. In this case, the spool 1 must be turned on and off every few bonding operations, but it is difficult to turn the spool 1 on and off at high speed, making it difficult to perform the bonding process at high speed.

In addition, when a capillary is used as the bonding tool 5 to perform ball bonding, a half clamp 12 is used to set the relative position of the formed ball and the capillary to a predetermined position.
An attempt was also made to move the wire from the first bonding section to the second bonding section while half-clamping the wire with the half clamp 12, but it was difficult to maintain the wire at a predetermined tension.

The present invention attempts to solve the above-mentioned conventional problems, and aims to provide a wire feeding device for a wire bonding apparatus that can feed the wire with a substantially constant tension.

[Means for solving problems]

The present invention provides a wire feeding device for a wire bonding apparatus equipped with a wire feeding amount control device that controls the feeding amount of the wire according to the amount of deflection when air is blown onto the wire. A tensioning device is provided for applying tension to the wire by blowing air to the wire between the wires, and a friction device is provided for applying frictional resistance to the wire between the tensioning device and the feeding amount control device. This is a wire feeding device for wire bonding equipment.

[Action]

The wire feeding device in the wire bonding apparatus of the present invention includes a tensioning device in the wire path between the feeding amount control device and the bonding tool, and a friction device in the wire path between the feeding amount controlling device and the tensioning device. If the amount of air blown from the tensioning device, the amount of air blown out by the amount control device, and the frictional force between the friction device and the wire are set appropriately, the amount of wire blown out (on the upstream side of the friction device) can be adjusted as appropriate. The tension of the wire can be maintained at approximately a predetermined optimum tension during the movement of the wire bonding from the first bonding part to the second bonding part, that is, at the time of loop formation, without being affected by the tension of the wire. Therefore, the wire can be supplied with almost optimal tension, and the wire will not break, sag, or curl when forming the loop.
Wire bonding can be performed well.

〔Example〕

An example of the present invention will be explained using FIG. 1.
In the embodiment of the present invention, a friction device 13 and a tension applying device 14 are appropriately attached to the bonding head 3 in addition to the devices of the conventional example described above. The friction device 13 is provided in the wire path immediately downstream of the feed-out amount control device 8, and a tension applying device 14 is provided in the wire path between the friction device 13 and the guide 7 to apply tension to the wire by blowing air onto the wire. It is provided. Note that the air blowing direction of the feeding amount control device 8 and the feeding direction of the spool 1 are opposite to those shown in FIG. This can be determined as appropriate.

The friction device 13 applies frictional resistance to the wire between the feeding amount control device 8 and the tension applying device 14, and controls the bending of the wire by the feeding amount controlling device 8 and the bending of the wire by the tension applying device 14 between the two. It consists of a guide piece 13A provided to hold the wire and a guide piece 13B for inserting and holding the wire between the guide piece 13A.
13B so that the frictional force with the wire can be adjusted. Guide piece 1
As the material for the friction surfaces 3A and 13B, felt, dustless filter, etc. are used. Note that the guide piece 13A may vary depending on the material, length along the wire, etc.
Alternatively, only one of the guide pieces 13B may be used.

During bonding, immediately after the first bonding is completed, that is, in a state where the bonding tool 5 has not moved from the first bonding part,
The fixed amount of air sprayed by the tensioning device 14 and the frictional resistance of the friction device 13 are selected so that the wire in the wire path between the friction device 13 and the first bonding section has the optimum tension, and the amount of feeding is controlled. The tension of the wire in the wire path from the spool 1 to the friction device 13 obtained by air blowing by the device 8 is smaller than the minimum tension of the wire downstream of the friction device 13, which will be described later, even at the maximum. By setting the spray amount and the length of the wire path, when the tension of the wire in the wire path downstream from the friction device 13 exceeds the optimum tension along the direction of wire supply, the wire path upstream from the friction device 13 is set. Allow the wire to slide downstream.

As the sensors 10 and 11, optical sensors, touch sensors based on electrical contact, etc. are used.

Thus, when the first bonding is completed, the wire has the optimum tension shown by the solid line.
When the bonding tool 5 is moved toward the second bonding part in this state, the wire tends to move in a direction where the tension becomes larger than the optimum tension, that is, to the position shown by the two-dot chain line. However, when the tension becomes larger than the optimum tension, the wire slips out of the friction device 13 and travels downstream against the frictional resistance of the friction device 13, so that the tension of the wire downstream of the friction device 13 is Approximately the optimum tension can be maintained during the movement to the second bonding part. During this time, the wire of approximately the length required for one bonding slides through the wire friction device 13 and travels downstream, and the wire on the upstream side
The length of the wire being unwound from the spool 1 is reduced by one length.

Therefore, the first bonding part and the second bonding part are connected by a wire having an optimal loop shape.
Can be bonded.

After the second bonding at the second bonding section is completed, the wire is cut and moved to the next first bonding section, but at this time, the height of the tip of the wire is changed. That is, at this time, the friction device 13
The height of the tip of the wire relative to the friction device 13 changes, and the tension of the wire downstream of the friction device 13 also changes. However, in the commonly used bonding method, even if the wire is clamped by the clamp 4 to maintain the height during wire cutting or movement and the wire tip is lifted, the wire tip is lowered again at the next first bonding section. More specifically, if a capillary is used as the bonding tool 5, the length of the wire will be slightly shorter due to ball formation, and if a wedge is used, the length of the wire will be slightly shorter due to the bending contact with the first bonding part. becomes shorter. Therefore, in most cases, the tension of the wire downstream of the friction device 13 is at the optimum tension by the time the next first bonding is performed, and the subsequent bonding can also be performed using the wire at the optimum tension.

[Effect of idea]

The present invention provides a tensioning device that applies tension to the wire by blowing air onto the wire between the payout amount control device and the bonding tool, and a friction device that applies frictional resistance to the wire between the tensioning device and the payout amount control device.
To provide a wire that can be supplied with an optimum tension at all times without being affected by the amount of wire payout, and therefore, during bonding, the wire bonding a first bonding portion and a second bonding portion can be always formed into an optimum loop shape without breaking, sagging, curling, or the like.

[Brief explanation of the drawing]

FIG. 1 is a front view of an embodiment of the present invention, and FIG. 2 is a front view of a conventional example. 1... Spool, 2... Motor, 3... Bonding head, 4... Clamp, 5... Bonding tool, 6... Bonding arm, 7...
Guide, 8... Feeding amount control device, 9... Air outlet, 10... Sensor, 11... Sensor,
12...Half clamp, 13...Friction device, 1
3A, 13B... Guide piece, 14... Tension applying device.

Claims (1)

[Scope of utility model registration request] In a wire supply device for a wire bonding apparatus, which is equipped with a payout amount control device that controls the payout amount of the wire according to the amount of deflection when air is blown onto the wire, the wire is connected between the feedout amount control device and the bonding tool. A wire bonding device comprising: a tension applying device that applies tension to the wire by blowing air to the wire; and a friction device that applies frictional resistance to the wire between the tension applying device and the feeding amount control device. wire feeding device.