JPH0357232A - Wire bonding apparatus - Google Patents

Abstract

PURPOSE:To enhance a productivity by a method wherein a means to measure a movement quantity of a capillary and a means to measure a time during which the capillary is moved by a prescribed divided quantity are installed and a velocity of the capillary is computed on the basis of their measured values. CONSTITUTION:A position detector 40 measures a rocking angle of a rocking arm 1 by adding a four-multiplication clock at a forward rotation of the rocking arm 1 and by substracting it at a backward rotation according to forward/ backward rotation signals. An operation part 53 of a velocity detector 50 computes [the rocking angle at a sampling time/the sampling time] as a rocking velocity when a rocking angle transmitted from a counter 52 is larger than a prescribed quantity, and computes [an angle corresponding to one clock of the four-multiplication clock/a four-multiplication clock time interval] as the rocking velocity. When an electric signal of a moving coil 4 is controlled by a rocking angle signal and a rocking angular-velocity signal, a displacement of a capillary and a bonding velocity can be set arbitrarily.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a wire bonding device. [Prior art] As a conventional technology, for example, Japanese Patent Publication No. 64-10093
There is a wire bonding device described in the publication. A conventional wire bonding device includes a swinging arm that can swing freely around a support shaft installed in a frame, a capillary attached to the tip of the swinging arm, and a drive motor that swings the swinging arm. and a position detector that detects the displacement of the swing arm and the velocity by differentially converting this displacement.

A conventional wire bonding device will be described in detail with reference to the drawings.

FIG. 2 is a side view showing a conventional example.

The wire bonding device shown in FIG.
01 is able to swing around an axis 102 as shown by arrow B, and a capillary 1o3 is attached to one end of the capillary 1o3, and a moving coil 104 is attached to the other end.

The moving coil 104 is located within a gap in a magnetic circuit 105 composed of a permanent magnet and a yoke (not shown), and by passing a current through the moving coil 104, the arm 1 is moved.
Drive 01.

A bracket 108 is fixed to the moving coil 104, and a probe 105 that can move forward and backward in the axial direction of a position detector 106 fixed to a frame 109 is in contact with the tip of the bracket 108.

The position detector 106 is connected to a differential circuit (not shown), and the speed can be determined from the output thereof. Therefore, when a current is applied to the moving coil 104, the swinging arm 101 moves to the axis 1.
The capillary 103 attached to the swing arm 101 also moves up and down in accordance with the movement.

At this time, as the swing arm 101 swings, the bracket 1
08 moves up and down, and its stroke is detected by the position detector 106. Thereby, the position detector 106 detects the position of the capillary 103, and also detects the speed by converting its output with a differentiating circuit.

Generally, in wire bonding equipment, the capillary is
When making contact with the electrode pad or lead frame of C, moving at a low speed to avoid collision with them has a great effect on the stability and quality of bonding.

[Problem to be solved by the invention]

The conventional wire bonding equipment described above measures the speed by differentially converting the capillary position signal, so it is not possible to accurately measure the speed when the capillary position does not change much, that is, when the capillary is moving at a low speed. is not possible. For this reason, when the capillary comes into contact with the IC's electrode pad or lead frame, it cannot be moved accurately and at low speed, which tends to cause cracks and adhesion under the pad, resulting in unstable bonding and poor quality. Since the bondability was low, there was a drawback that productivity deteriorated.

[Means to solve the problem]

The wire bonding apparatus of the present invention includes: (A) a position detection means for measuring the amount of movement of the capillary through the gold-Nl thin wire; (B) a time measurement means for measuring the time it takes for the capillary to move by a predetermined step amount; C) Calculating means for calculating the speed of the capillary based on the detected value from the position detecting means and the measured value from the time measuring means. It consists of:

〔Example〕

Next, the present invention will be explained in detail with reference to the drawings. FIG. 1 is a block diagram showing one embodiment of the present invention.

The wire bonding apparatus shown in FIG.
is capable of swinging around a swinging shaft 2 as shown by arrow A, and a capillary 3 is attached to the tip of the swinging arm 1, and a moving coil 4 is attached to the other end.

The moving coil 4 is located within the gap of a magnetic circuit 5 composed of a permanent magnet and a yoke, and constitutes a swing motor, and the arm 1 is driven by passing a current through the moving coil 4. The capillary 3 holds the gold wire 8,
Press the tip of the gold wire 8 to the bonding pad of the pellet 9 to perform bonding. Further, a rotary encoder 10 is attached to the swing shaft 2 of the swing arm 1 to detect the amount of swing of the swing arm 1. A waveform shaper 20 and a direction detector 30 are connected to the rotary encoder 10, and a position detector 40 and a speed detector 50 are connected to the waveform shaper 20 and direction detector 30.

The rotary encoder 10 has A-phase and B-phase 2 which repeats high level and low level every predetermined rotation amount (for example, 4 seconds).
A phase pulse is output, and when the swing arm 1 rotates in the normal direction, the A phase advances by 90 degrees with respect to the B phase, and when the swing arm 1 rotates in the reverse direction, it lags behind by 90''.

The direction detector 30 detects the swing arm 1 depending on the state R of the B phase (high level or low level) when the A phase rises or falls, or the state of the A phase when the B phase rises or falls. It measures whether the rotation is forward or reverse, and sends a forward/reverse rotation signal to the position detector 40 and speed detector 50. The waveform shaper 20 creates pulses using the rising and falling edges of the A-phase and B-phase pulses, and generates a quadruple clock. The position detector 40 measures the swing angle of the swing arm 1 by adding a quadruple clock when the swing arm 1 is rotating in the normal direction and subtracting it when the swing arm 1 is rotating in the reverse direction, according to the forward/reverse rotation signal. Next, the operation of the speed detector 50 will be explained. The speed detector 40 includes a counter 51, a timer 52, and an arithmetic unit 53. The counter 51 receives a quadruple clock and a forward/reverse rotation signal, and the timer 52 receives a quadruple clock. The counter 51 adds a quadrupled clock during normal rotation and subtracts it during reverse rotation, according to the forward/reverse rotation signal at every predetermined period (here, the sampling time of the controller of the wire bonder). Measure the swing angle. The timer 52 measures the time interval of the quadruple clock. When the swing angle sent from the counter 5l is larger than a predetermined amount (that is, when the swing speed is large), the calculation unit 53 calculates
For this, calculate [(swing angle at sampling time)/(sampling time>] as the swing speed, and if it is small, calculate [(angle equivalent to 1 clock of quadruple clock)/(
(time interval of quadruple clock)] is calculated as the swing speed.

Also, the direction detector 30 can measure the rotation direction for each quadruple clock, but if the rotation direction of the current quadruple clock is different from the previous rotation direction of the quadruple clock, the speed is set to zero. ．． During high-speed operation, the amount of movement during the sampling period is large, but the time interval of the quadruple clock is short, so it is more accurate to calculate from the amount of movement; conversely, during low-speed operation,
Although the time interval of the multiplication clock is long, the amount of movement during the sampling period is small, so it is more accurate to calculate the speed from the time interval of the quadruple clock. By controlling the current of the moving coil 4 to MtH based on the swing angle signal and the swing angular velocity signal, the capillary displacement and bonding speed can be set arbitrarily. In this embodiment, a device for measuring the amount of swinging of the swinging arm for each predetermined period and a device for measuring the amount of swinging of the swinging arm are installed separately. The amount of oscillation of the oscillating arm for each period may be calculated by subtracting the amount of oscillation in the current period from the amount of oscillation in the current cycle. Further, since calculating the speed using this method is equivalent to calculating the speed by differentially converting the position, the speed during high-speed movement may be calculated by differentially converting the position. The swing J of the swing arm during a predetermined period distinguishes between high speed and low speed.
It is not the size of i (velocity calculated by differential transformation of position),
It may be performed at the time interval (speed calculated from) of the quadruple clock. [Effects of the Invention] The wire bonding apparatus of the present invention calculates the speed from the amount moved in a predetermined period during high-speed operation, and calculates the speed from the time it takes to move a predetermined amount during low-speed operation. Since the speed of the capillary can be measured with high precision, stable bonding is possible, bonding quality is high, and productivity can be improved.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, and FIG. 2 is a side view showing a conventional example. 1... Swinging arm, 2... Axis, 3...
... Capillary, 4 ... Moving coil, 5 ... Magnetic circuit, 8 ... Gold wire, 9.
...Bellet, 10...Rotary encoder, 20...Waveform shaper, 30...
Direction detector, 40...Position detector, 50...
...Speed detector, 5l...Timer, 52...
... Counter, 53 ... Arithmetic device.

Claims (1)

[Scope of Claims] (A) Position detection means for measuring the amount of movement of the capillary through a thin metal wire; (B) Time measurement means for measuring the time it takes for the capillary to move by a predetermined step amount; (C) The above. Calculating means for calculating the speed of the capillary based on the detected value from the position detecting means and the measured value from the time measuring means. A wire bonding device comprising: