JPH04184947A - Wire-bonding device - Google Patents

Abstract

PURPOSE:To avoid the excessive wire feeding by inertia even in the rapid wire- bonding operation by a method wherein an impressing means of supplementary tension is provided between a clamper and an air tension mechanism. CONSTITUTION:A taper through hole 4 in opening diameters of about 0.3mm and 0.1mm respectively on a clamper 3 side and an air tension mechanism 5 side is made in a member 41 about 15mm long and then a wire 7 in diameter of 20-40mum is inserted into the through hole 42. Next, a duct 43 reaching the through hole 42 is provided close to the end on the mechanism 5 side of the member 41. In such a constitution, an air flow from the end of the clamper 3 side to the mechanism 5 side is excited in the through hole 42 so that the supplementary tension impressed by a tension impressing means 4 may be adjusted to the specified value by controlling the air flow rate.

Description

[Detailed Description of the Invention] [Summary] This invention relates to an apparatus for bonding wires to a semiconductor integrated circuit chip.

The object of the present invention is to enable a wire of a desired shape to be installed between the chip and the lead portion of a lead frame with good reproducibility.

A capillary that presses and joins a wire to a semiconductor integrated circuit chip, a clamper that grips the wire supplied to the capillary at a predetermined timing, and a tension applying means that applies tension to the wire supplied to the clamper. The tension applying means includes a member provided with a tapered through hole that contracts in the opposite direction from the clamper side into which the wire is inserted, and an airflow flowing in the opposite direction from the clamper into the through hole. and a means for causing the phenomenon to occur.

[Industrial application field]

The present invention relates to an apparatus for bonding wires to semiconductor integrated circuit chips.

A wire bonding device connects a semiconductor integrated circuit chip (hereinafter abbreviated as a chip) bonded to a lead frame and a lead portion of the lead frame.

This is a device for constructing a wire made of gold or copper, etc., with a diameter of about 30μ, and is shown in Figs. 6(a) and (b).
As shown in FIG. 3, a wire 7 fed through the inside of the capillary l is connected to a bonding pad 8. which is provided around the chip 8. After bonding, the capillary 1 is moved to the lead portion 9 of the lead frame while continuing to supply the wire 7, and the wire 7 is bonded to the lead portion 9. When the wire 7 is installed between the pair of bonding pads 8I and the lead portion 9.

The wire 7 is cut at the tip of the capillary l, and the wire 7 is similarly installed between another bonding pad 8I and the lead portion 9.

The wire 7 installed as described above is shown in FIG.
As shown in the cross-sectional view, an upward curvature is provided. This is because the wire 7 may be cut due to tension when the distance between the bonding pad 8I and the lead portion 9 changes due to thermal expansion, or the bonding pad 8I may
In order to prevent it from peeling off from the lead part 9,
This is also to prevent the edge of the chip 8 and the wire 7 from coming into contact with each other.

[Conventional technology]

The above-mentioned curved shape is created during the construction process of the wire 7.
It is formed by displacing the capillary 1 in three-dimensional directions: up and down, back and forth, and right and left. This will be explained in more detail with reference to FIG.

The wire 7 wound on the reel 6 is supplied to the capillary 1 through the first clamper 2 and the second clamper 3.

A predetermined tension is always applied to the wire 7 by an air tension mechanism 5 provided between the reel 6 and the clamper 3. In FIG. 4, reference numeral 10 denotes a support arm for holding and moving the capillary 1, and when the wire 7 at the tip of the capillary 1 is joined to the chip 8 and the lead part 9 of the lead frame by ultrasonic waves,
It also serves as a horn for transmitting ultrasonic energy.

capillary l, clampers 2 and 3. The air tension mechanism 5 and the support arm lO are connected to the wire 7 and the tip 8.
In the movement of the bonding head accompanying the bonding with the lead portion 9, the bonding head moves as one. Clamper 2
and 3 indicate the wire 7 in the movement of the cabilla +71 upwards, that is, away from the chip 8 or the lead part 9.
grasp it.

In the process in which the capillary l moves downward, that is, approaches the chip 8 or the lead portion 9, it operates to release its grip on the wire 7. The relationship between the movement of the capillary 1 and the operations of the clampers 2 and 3 and the air tension mechanism 5 is shown in the timing diagram of FIG. 5, except for the movement of the capillary 1.

It is represented by the components in the vertical direction.

Generally, after the wire 7 is bonded to the chip 8, the capillary 1 approaches the lead part 9 while moving upward in a convex arc between the chip 8 and the lead part 9.
Wire 7 is joined to lead portion 9. Then, when the wire 7 is cut at the tip of the capillary 1 by a cutting mechanism (not shown), the capillary 1 moves upward again and moves to the next bonding pad 8.9 on the chip 8. approach. Fifth
As shown in the figure, the wire 7 is gripped by the clamper 3 only during the first half of the downward movement of the capillary l, and is released from gripping by the clampers 2 and 3 during the latter half. On the other hand, as the capillary 1 moves upward, it is gripped by clampers 2 and 3. This is to keep the wire 7 slightly protruding from the tip of the capillary 1 when the capillary 1 moves upward.

(Problem to be Solved by the Invention) The shape of the arc of the wire 7 installed between the chip 8 and the lead part 9 as described above is determined by the motion path and moving speed of the capillary 1, the elastic force of the wire 7, and the air tension. It changes slightly depending on the tension caused by the mechanism 5, the frictional force caused by the clampers 2 and 3, etc. Also.

Even in the same chip, the distance between the bonding pad and the corresponding lead portion is not constant, and the shape changes greatly depending on this distance.

Incidentally, as semiconductor integrated circuits become denser and the number of external connection terminals increases, the distances between adjacent bonding pads and between adjacent lead portions become smaller. As a result, the wire installed as described above may be slightly deformed.

Adjacent wires come into contact with each other more easily. Such deformation is also increased by the flow of the resin during the molding process in which the chip is embedded in the resin.

Therefore, it is basically required to construct the wire so that it has a predetermined shape.

However, when attempting to bond a large number of wires at high speed to semiconductor device chips that are becoming more densely packed as described above, the shapes of the raised wires greatly vary and deform, resulting in defects due to contact between the wires as described above. There was a problem that got easier. Particularly, in the case of a relatively soft wire such as a gold wire, there is a problem in that the shape varies greatly and the bonding speed must be lowered.

Furthermore, in recent years, there has been a trend to make semiconductor integrated circuit packages thinner (lower in height), and as a result, it has become necessary to reduce the height of the curved shape of the wire installed between the chip and the lead portion. For this.

There is an increasing demand for the ability to handle various shapes of the arcs of the construction wire, but it has been difficult for conventional wire bonding equipment to handle this.

SUMMARY OF THE INVENTION An object of the present invention is to provide a wire bonding device that can solve the above-mentioned problems and meet new demands.

[Means to solve the problem]

The above objects include a capillary that presses and joins a wire to a semiconductor integrated circuit chip, a clamper that grips the wire supplied to the capillary at a predetermined timing, and a tension application that applies tension to the wire that is supplied to the clamper. The tension applying means includes a member provided with a tapered through hole that contracts in the opposite direction from the clamper side into which the wire is inserted, and a member provided with a tapered through hole that contracts in the opposite direction from the clamper side into the through hole. This is achieved by the wire bonding apparatus according to the present invention, which is characterized in that it is equipped with means for generating a directional airflow.

[For production]

In the conventional wire bonding apparatus, the tension applied to the wire 7 while the capillary 1 is descending is mainly applied by the air tension mechanism 5. However, the air tension mechanism 5 blows air ejected from a nozzle from the side onto the wire 7, which has a diameter of about 30 μm. Not enough tension was applied. Therefore, when the wire 7 released from the grips of the clampers 2 and 3 is pulled downward at high speed by the capillary l, due to its own inertia,
Since an extra length of wire 7 is supplied from the capillary 1, the shape of the construction wire varies and deformation is likely to occur.

Although this problem can be alleviated by reducing the bonding speed, a decrease in bonding efficiency is unavoidable.

In the present invention, as shown in FIGS. 1(a) and (b), a second tension applying means 4 for applying additional tension is added between the clamper 3 and the air tension mechanism 5. Even in high-speed bonding operations, extra wire 7 is prevented from being supplied due to inertia. The second tension applying means 4 is a member 4 provided with a through hole 43 through which the wire 7 passes, as shown in FIG.
1 and 1 through hole 4. Wire 7 and member 4 within. The air tension mechanism 5 is inserted from the end on the clamper 3 side into the gap between the
The end of the example comprises a means for generating such an airflow within the interior.

Such second tension applying means 4 is fixed to the bonding head together with the air tension mechanism 5.

As a result, a tension that is sufficiently larger than that of the air tension mechanism 5 can be applied to the wire 7.

Since the tension can be changed by controlling the flow rate of the airflow, the wire 7 having a desired curved shape can be installed between the chip 8 and the lead portion 9.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

In the following drawings, the same parts as in the previously shown drawings are designated by the same reference numerals.

FIG. 2 is a schematic cross-sectional view for explaining one embodiment of the structure of the second tension applying means 4. As shown in FIG.

For example, the length (L) made of metal or non-metal is about 15
+++m member 4I is provided with a tapered through hole 48 having opening diameters of approximately 0.3 mm and 0.1 m+n at the end on the clamper 3 side and the end of the five air tension mechanisms 93, respectively. , inside this diameter 20~
The wire 7 of 40a- is inserted.

Member 4. 9 near the end of the air tension mechanism 5 side.
For example, perpendicular to the side surface of the member 41, and one through hole 4. Conduit reaching 4. One or more are provided.

Further, a member 4.0 is provided with a groove 4° for guiding the conduit 4s to an external vacuum exhaust pipe 4h. is fixed to the bonding head together with clampers 2 and 3, etc., and is connected to the vacuum exhaust pipe 4.
h is connected to a vacuum evacuation device (not shown) through two flexible tubes (not shown). Vacuum exhaust pipe 4. When the wire 7 is evacuated, air flows into the through hole 4 from the end of the clamper 3, creating an airflow toward the air tension mechanism 5, which causes tension to be applied to the wire 7 toward the air tension mechanism 5. is applied.

The relationship between the movement of the capillary l and the operations of the clampers 2 and 3, the air tension mechanism 5, and the second tension applying means 4 in the configuration of the present invention is shown below.

This is shown in the timing explanatory diagram of FIG. However, the movement of the capillary 1 is represented by the vertical component. As shown in the figure, the tension by the second tension applying means 4 is applied in synchronization with the timing at which the wire 7 is released from the clamper 3. By controlling the exhaust speed through the vacuum exhaust pipe 46, the magnitude of the tension applied by the second tension applying means 4 can be adjusted to a desired value. The optimum setting of the operation timing and tension of the second tension applying means 4 depends on the moving speed of the capillary l, the distance between the tip 8 and the lead part 9, the hardness of the wire 7, and the length of the bridge between the tip 8 and the lead part 9. It is determined experimentally depending on the curved shape of the wire 7.

(Effects of the Invention) According to the present invention, when the wire is installed between the chip and the lead portion at high speed, excess wire is prevented from being supplied due to its own inertia. Therefore, the moving speed of the capillary Restrictions caused by wire materials and wire materials are relaxed.
The degree of freedom in designing the curved shape of the installation wire is expanded, and wires with more complicated curved shapes required for semiconductor devices and high-density semiconductor integrated circuits that require thin packages can be installed. As a result, contact between the erection wires is reduced.

This has the effect of improving the manufacturing yield and reliability of these semiconductor devices.

[Brief explanation of the drawing]

FIG. 1 is a diagram explaining the principle of the present invention. FIG. 2 is an explanatory diagram of an embodiment of the structure of the second tension applying means 4 in the present invention. FIG. 3 is an explanatory diagram of the operation timing of the second tension applying means 4 in the present invention. FIG. 4 is a schematic configuration diagram of a conventional wire bonding device. FIG. 5 is an explanatory diagram of the operation timing of each part of a conventional bonding head. FIG. 6 is a schematic explanatory diagram of the wire bonding method. In fig. ■ is a capillary, 2 and 3 are clampers. 4 is a second tension applying means. 5 is an air tension mechanism. 6 is the reel, 7 is the wire, and 8 is the chip. 9 is a lead part, 10 is a support arm. 4 is a member; 4. is a through hole. 4 is an airflow generating means, and 44 is a groove. 4. is a conduit + 4h is a vacuum exhaust pipe. 8I is a bonding pad. '11 Group d Meng Qi's wire bodane 7° fold position, F existing atmosphere lecture or mouth%
4 Diagram 1: Pocket view of wire bossing capacity! Tochimo Rom No. 6
figure

Claims (1)

[Claims] A capillary that presses and joins a wire to a semiconductor integrated circuit chip, a clamper that grips the wire supplied to the capillary at a predetermined timing, and a tension force applied to the wire supplied to the clamper. a member provided with a tapered through hole that contracts in the opposite direction from the clamper side into which the wire is inserted; A wire bonding device characterized by comprising: means for generating an airflow in the opposite direction from the opposite direction.