JPS6046541B2 - Ultrasonic bonding equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an ultrasonic bonding apparatus for ultrasonically bonding a bonding member to an object to be bonded.

FIG. 1 is a block diagram of a conventional ultrasonic bonding apparatus. In the figure, 1 is an ultrasonic oscillation circuit, and an ultrasonic oscillation output signal outputted from this ultrasonic oscillation circuit 1 is supplied to an ultrasonic transducer 2. The ultrasonic vibrator 2 vibrates upon receiving the ultrasonic oscillation output signal, and the vibration is supplied to the bonding tool 4 via the ultrasonic horn 3. The bonding tool 4, ultrasonic horn 3, and ultrasonic vibrator 2 are integrally moved in the vertical direction in the figure by a moving mechanism (not shown). Furthermore, a bonding wire 5 is installed on the bonding tool 4, and the ultrasonic oscillation circuit 1 is activated when the bonding tool 4 reaches the upper and lower ends. At this time, if an object to be bonded, such as an IC pellet 6, is present on the opposing surface of the bonding tool 4, ultrasonic bonding will be performed with the bonding wire 5 pressed against any position of the object to be bonded 6. FIG. 2 shows a waveform diagram showing changes in the vertical movement of the tip of the bonding tool 4, as well as a diagram showing the operation timing of the ultrasonic oscillation circuit 1.

As shown in the figure, the ultrasonic oscillation circuit 1 starts oscillating when the bonding tool 4 reaches the lower end, and continues oscillating until it rises again. However, since the moving distance L from the upper end to the lower end of the bonding tool 4 is fixed, the bonding object 6 to be bonded
If there are variations in the thickness, reliable bonding will not be possible. That is, if the thickness of the bonded object 6 is thicker than the specified thickness, the bonding wire 5 is moved to the bonded object 6 only by the load applied to the bonding tool 4 before the ultrasonic oscillation circuit 1 oscillates.
is pressed against. After this, ultrasonic vibrations will be applied to the bonding tool 4, but in this state, the frictional forces between the bonding tool 4 and the bonding wire 5, and between the bonding wire 5 and the bonded object 6 are extremely high. As a result, burrs occur between each ink, making it impossible to obtain sufficient bonding ink strength.
That is, when bonding is performed using a conventional ultrasonic bonding device, its reliability is low.
The present invention has been made in consideration of the above circumstances, and its purpose is to provide an ultrasonic bonding apparatus that can perform highly reliable bonding. An embodiment of the present invention will be described below with reference to the drawings.

FIG. 3 is a block diagram of one embodiment of the present invention.

The difference between the figure and the conventional one is that a predetermined voltage is applied between the bonding tool 4 and the bonded object 6 by a power source 7, and the bonding tool 4, the power source 7, and the bonded object 6 are In the middle of the route, a current detection section 8 for detecting the current flowing in this route is provided. Further, the ultrasonic oscillation circuit 1 is supplied with the output of the current detection section 8, and the ultrasonic oscillation circuit 1 is connected to the current detection section 8.
It is controlled so that it operates only during the period when the sensor is detecting current. With such a configuration, if the thickness of the bonded object 6 is thicker than the specified value, the bonding tool 4 comes into contact with the bonded object 6 through the bonding wire 5 when descending. Current detection section 8, power supply 7, and bonded object 6
Since this forms a closed loop, the ultrasonic oscillation circuit 1 will operate even if the bonding tool 4 has not reached the lower end. In other words, the load caused by the bonding tool 4! As the weight is applied to the bonding object 6 and ultrasonic vibrations are supplied to the bonding tool 4, the bonding tool 4 and the bonding wire 5, and the bonding wire 5 and the bonding object, respectively, as in the conventional case. During this period, burrs will not occur. Therefore, sufficient bonding strength can be obtained even when the thickness of the bonded object 6 is thicker than specified. This also means that even if there is a variation in the thickness of the bonded object 6, it can be dealt with, so it is possible to use a relatively low-priced bonded object 6 that does not require strict control of its thickness. l can also be done. Note that the present invention is not limited to the one embodiment described above; for example, in the embodiment described above, a case will be described in which the contact state between the bonding tool 4 and the bonded object 6 is detected by detecting the current between the two. However, it goes without saying that this may be detected by other methods.

As explained above, according to the present invention, the contact state between the pressure welding object and the bonded object is detected, and when the two come into contact, the ultrasonic oscillation circuit is activated, and the ultrasonic vibrator is vibrated with the output thereof. By supplying the vibration of the ultrasonic vibrator to the press-contacting body, it is possible to provide an ultrasonic bonding apparatus that can perform highly reliable bonding.

[Brief explanation of the drawing]

Figure 1 is a configuration diagram of a conventional ultrasonic bonding device, Figure 2
The figure shows a waveform diagram and a timing diagram for explaining the operation of the conventional device, and FIG. 3 shows a configuration diagram of one embodiment of the present invention. 1... Ultrasonic oscillation circuit, 2... Ultrasonic vibrator, 3...
... Ultrasonic horn, 4... Bonding tool, 5.
...Bonding wire, 6...Bonded object,
7...Power supply, 8...Current detection unit.

Claims (1)

[Claims] 1. An ultrasonic oscillation circuit, an ultrasonic vibrator that vibrates by the output of the ultrasonic oscillation circuit, a press-contact body that presses a bonding member against a bonding object to which the vibration of the ultrasonic vibrator is transmitted, and the press-contact body. a means for moving the object to be bonded and the object to be bonded; and a detection means for detecting a contact state between the press-welded object and the object to be bonded by applying a predetermined voltage between the two and detecting a current flowing between the two; An ultrasonic bonding apparatus characterized in that the oscillation circuit is configured to operate only when contact is detected by the detection means.