JPH0298149A - Wire boding apparatus - Google Patents

Abstract

PURPOSE:To eliminate the application of an excessive pressure to a bonding pad by composing a moving coil of two coils. CONSTITUTION:A speed command circuit 10 drives both first and second coils 41, 42 of a moving coil 4 until a capillary moves down from above a pellet to a predetermined height, and the capillary is operated according to a profile. When the capillary 3 arrives at the predetermined height, the circuit 10 outputs a low constant speed signal, and feeds a coil switching signal to a driving circuit 14. The circuit 14 cuts off the current applied to the coil 41, drives the capillary 3 at a low speed by applying a current only to the coil 42, and moves it down until it is brought into contact with a pellet 9. When the capillary 3 is brought into contact with the pellet 9 and the output of a speed detector 7 becomes zero, a switching circuit 13 applies a predetermined current to the coil 42 to apply a predetermined bonding pressure to the pellet. Thus, since the braking property of a rocking ara 1 can be enhanced, an excessive pressure is not applied to a bonding pad.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a wire bonding device, and particularly to a wire bonding device that can be applied to the assembly process of semiconductor devices.

[Conventional technology]

As a conventional technique, for example, Japanese Patent Publication No. 62-43336
There is a wire bonding device as shown in the publication.

Conventional wire bonding equipment has a capillary at one end and a moving coil at the other end that can swing in a plane perpendicular to the magnetic flux within the air gap of a magnetic circuit consisting of a permanent magnet and a yoke. The device includes a swinging arm that cooperates to form a swinging motor, a position detector that detects the swinging angle of the swinging arm, and a speed detector that detects the swinging speed.

In this wire bonding device, a swinging arm moves according to a predetermined nine-speed profile until the capillary approaches a predetermined distance from a bonding pad of a semiconductor pellet while detecting the outputs of a position detector and a speed detector.
After the capillary reaches a predetermined distance, the swinging arm approaches the bonding pad at a constant speed, and after the capillary contacts the bonding pad and the output of the speed detector becomes zero, a constant current is applied to the moving coil. The current in the moving coil is controlled so that it flows.

Next, a conventional wire bonding apparatus will be described in detail with reference to the drawings.

FIG. 4 is a perspective view showing an example of a conventional wire bonding device. In FIG. 4, the swing arm 1 can swing around the shaft 2 as shown by the arrow in the figure, and a capillary 3 is attached to one end of the swing arm 1, and a moving coil 104 is attached to the other end. There is.

The moving coil 104 is located in the air gap of the magnetic circuit 5 composed of the permanent magnet 51 and the yoke 52, and by passing a current through the moving coil 104, the arm 1 is driven, and the position and speed of the arm 1 are determined by the axis 2. It is detected by a position detector 6 and a speed detector 7 attached to the vehicle. The capillary 3 holds the gold wire 8 and presses the tip of the gold wire 8 against the bonding pad of the semiconductor pellet 9 for bonding.

Next, the multi-operation will be explained with reference to FIG. Speed command circuit 11
0 outputs a speed command signal to the comparison circuit 111 according to a profile set in advance so that the capillary can move in a short time until the capillary 3 descends from above the pellet 9 to a predetermined height, and the speed command signal is output from the comparison circuit 111. The difference signal obtained is selected by the switching circuit 113, passes through the drive circuit 114, and drives the moving coil 104.
Capillary 3 operates according to the profile. After the capillary 3 reaches a predetermined height, the speed command circuit 1 is activated to prevent the capillary 3 from colliding with the bonding pad.
A low constant speed signal is output from 10, and the capillary 3 descends at low speed and contacts Pele (109).

When the cavity 2 3 contacts the pellet 9 and the output of the speed detector 7 becomes zero, the switching circuit 113 selects a signal from the pressure command circuit 112 and applies a constant current to the moving coil 104 to move the pellet 9. Apply constant bonding pressure to the

However, the speed of the capillary 3 is very low until it contacts the bonding pad, so in order to detect whether it is moving or has zero speed, it is necessary to use filtering etc.
It takes a certain amount of time, and there is a slight time delay in the trap from when the capillary 3 actually contacts the bonding pad to when zero velocity is detected. Therefore, capillary 3
Even if the bonding pad makes contact with the bonding pad, the capillary 3 tries to move at the speed commanded by the speed command circuit 110 during this time delay. It will put pressure on you.

To this end, the conventional wire bonding apparatus described above is improved so that the current applied to the moving coil 104 is
A wire bonding apparatus has also been invented in which a vine is provided to prevent excessive pressure. However, in a wire bonder that performs high-speed bonding, in order to accelerate and decelerate the swinging arm in a short time, the thrust constant, which is the ratio of the driving force and current of the swing motor composed of the moving coil 104 and the magnetic circuit 5, is large. Since it generates a large pressing force even with a small current, it is difficult to completely control the delicate settings of the current resistor, and the drawback of applying excessive pressure to the bonding pad cannot be completely eliminated. There was a drawback that bonding reliability was low.

[Problem to be solved by the invention]

In the conventional wire bonding device described above, the thrust constant of the swing motor that drives the swing arm is high, so by providing a rivet in the current flowing through the moving coil, the pressing force when the capillary and bonding pad come into contact can be reduced. Even if the adjustment is made, it is difficult to completely control the delicate setting of the current flow rate, so there is a drawback that excessive pressure is easily applied to one bonding band and the bonding reliability is low.

[Means to solve the problem]

The wire bonding device of the present invention oscillates in a plane perpendicular to the magnetic flux within the air gap of a magnetic circuit consisting of a moving coil having at least two coils, a cavity at one end, and a permanent magnet and a yoke at the other end. a swinging arm that is movably provided with the moving coil and cooperates with the magnetic circuit to constitute a swinging motor; a position detector that detects the swinging angle of the swinging arm; and a position detector that detects the swinging angle of the swinging arm. It is configured to include a speed detector that detects the swing speed.

Further, in the wire bonding apparatus of the present invention, the moving coil has a first coil and a second coil, and the moving coil has a first coil and a second coil.
The number of turns of the coil is at least ten times the number of turns of the second coil.

Furthermore, in the wire bonding apparatus of the present invention, the wire bonding apparatus detects the output signals from the position detector and the speed detector until the cavity 2 reaches a predetermined distance from the bonding pad of the semiconductor pellet. A current is applied to the first coil and the second coil to move the swing arm according to a predetermined profile, and after the capillary reaches the predetermined distance, the swing arm approaches the bonding pad at a constant speed. After the capillary contacts the bonding pad and the output signal from the speed detector becomes zero, a constant current is applied to the second coil to and means for controlling the current of the moving coil.

〔Example〕

Next, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a perspective view showing an embodiment of the present invention, and FIG. 2 is a side view shown in the direction of the arrow in FIG.

In the wire bonding apparatus shown in FIG. 1, a swinging arm 1 can move Km around a shaft 2 as shown by the arrow in the figure, and a cabillar is attached to one end of the swinging arm 1. A moving coil 4 is attached to j3 and the other m. The moving coil 4 is composed of a first coil 41 and a second coil 42, as shown in FIG. The number of turns of the first coil 41 accounts for the majority of the number of turns of the moving coil 4, and in this embodiment, the number of turns of the first coil 41 is 20 times the number of turns of the second coil.

The moving coil 4 has a permanent magnet 51 and a yoke 5, respectively.
A swing motor, which is a so-called short coil type VCM (Voice Coil Motor), is configured in the air gap of the magnetic circuit 5 formed by the magnetic circuit 5, and the arm 1 is activated by passing current through the first coil and the second coil. drive Arm 1
The position and speed of are detected by a position detector 6 and a speed detector 7 respectively attached to the shaft 2. capillary 3
holds the gold wire 8 and presses the tip of the gold wire 8 against the bonding pad of the semiconductor pellet 9 to perform bonding.

Next, the operation of the bonding apparatus of the present invention will be explained with reference to FIG.

Until the capillary 3 descends from above the pellet 9 to a predetermined height, the speed command circuit 10 outputs a speed command signal to the comparator circuit 11 according to a profile set in advance so that the capillary can move in a short time. 1
1 is selected by the switching circuit 13, the driving circuit 14ei drives both the first coil and the second coil of the moving coil 4, and the capillary 3 operates according to the profile. When the capillary 3 reaches a predetermined height, a low constant speed signal is output from the speed command circuit 1O, and a coil switching signal is sent to the drive circuit 1.
Send to 4. The drive circuit 14 cuts off the current applied to the first coil 41 of the moving coil 4 by 4 ulk and applies a current only to the second coil 42 to drive the capillary 3 at a low speed until it descends until it contacts the pellet 9.

When the capillary 3 contacts the pellet and the output of the speed detector 7 becomes zero, the switching circuit 13 selects a signal from the pressure command circuit 12 and applies a constant current to the second coil 42 to apply a constant bonding pressure to the pellet 9. Add.

As mentioned above, one wire bonding apparatus of the present invention includes:
Even if there is a slight time delay from when the capillary 3 contacts the bonding pad to when zero velocity is detected, the oscillating motor composed of the magnetic circuit 5 and the second coil 42 is activated by applying current to the second coil 42. The thrust constant, which is the ratio of the driving force to the current, is as small as 1/21 compared to a swing motor constructed of a magnetic circuit -ξ by applying current to the first coil 41 and the second coil 42. The braking performance is improved and excessive pressure can be suppressed.

〔Effect of the invention〕

By changing the moving coil to a moving coil having a first coil and a second coil, the wire bonding apparatus of the present invention can reduce the thrust constant when pressurizing the bonding pad, and improve the braking performance of the swing arm. This has the effect of improving bonding reliability without applying excessive pressure to the bonding pad.

[Brief Description of the Drawings] Fig. 1 is a perspective view showing one embodiment of the present invention, and Fig. 2 is a perspective view showing an embodiment of the present invention.
3 is a block diagram showing the configuration of the control device of the embodiment shown in FIG. 1, FIG. 4 is a perspective view of a conventional example, and FIG. It is a professional diagram showing the configuration of the conventional example control device shown in the figure.・
...Cabin')% 41104...Moving coil, 5...Magnetic circuit, 6...
...Position detector, 7...Speed detector, 8...
...Gold wire, 9...Pellet), 10,110.
...Speed command circuit, 11,111.°°...Comparison circuit, 12°112.Pa...Pressure command circuit, 13,
113°゛°°°゛ switching circuit, 14,114...
...Drive circuit, 41...First coil, 42.
...Second coil, 51...Magnet, 52.
·····yoke. Agent Susumu Uchihara, Patent Attorney Figure Z Pigeon, Figure 3 Figure 4

Claims (1)

[Claims] 1. A moving coil having at least two coils, a capillary at one end, and a permanent magnet and a yoke at the other end. a swinging arm that is movably provided with the moving coil and cooperates with the magnetic circuit to constitute a swinging motor; a position detector that detects the swinging angle of the swinging arm; and a position detector that detects the swinging angle of the swinging arm. A wire bonding device comprising: a speed detector that detects a swing speed. 2. The wire bonding apparatus according to claim 1, wherein the moving coil has a first coil and a second coil, and the number of turns of the first coil is at least 10 times the number of turns of the second coil. 3. Until the capillary reaches a predetermined distance from the bonding pad of the semiconductor pellet, the first
A current is applied to the coil and the second coil to move the swing arm according to a predetermined profile, and after the capillary reaches the predetermined distance, the swing arm approaches the bonding pad at a constant speed. like second
A current is applied only to the coil, and after the capillary contacts the bonding pad and the output signal from the speed detector becomes zero, a constant current is applied to the second coil to control the current of the moving coil. 3. The wire bonding apparatus according to claim 2, further comprising control means.