JPS6050933A - Wire bonding device - Google Patents

Abstract

PURPOSE:To enable to obtain wire bonding of short time and excellent in junction strength by a method wherein transverse directional micro oscillation different in phase from the micro oscillation on the side of a bonding wire is given to pellets and a work stage. CONSTITUTION:The pellets 2 and a lead frame 3 are mounted on the work stage 1. Next, a CPU12 operates, selects the pad of the pellet 2, and leads the pad to the tip of a bonding tool 4. Then, the tip of the bonding wire 5 is put in contact, and the wire 5 is given the micro oscillation along the X-direction by means of an ultrasonic oscillator 6. On the stage 1, each linear motor 7a and 7b is so driven as to generate micro oscillation, and accordingly micro oscillation is given in the transverse direction of each of X-direction and Y-direction. Thereby, the frictional energy is rapidly increased by relative oscillations of different phases at the contact part between the pellet 2 and the wire 5, and then a large frictional heat can be obtained. Therefore, bonding excellent in junction strength can be performed in a short time.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an improvement of a wire bonding apparatus in which a wire is bonded using a vibration, particularly a minute vibration.

[Technical background of the invention and its problems]

2. Description of the Related Art In the assembly process of semiconductor devices, a wire bonding device is used as a means for connecting a pellet and a lead frame with a wire. In this type of wire bonding equipment, minute vibrations are used to
There are devices in which bonding wires such as gold wires and aluminum wires are bonded to the leads of the pellet and lead frame, respectively.

Conventionally, as shown in FIG. 1, a wire bonding device using such minute vibrations includes an ultrasonic vibrator C at the base of a bonding tool b that moves a bonding wire a such as a gold wire or an aluminum wire to be fed out.
A binding wire (a) is provided with a pad (not shown) of a pellet (e) mounted on a work stage (d) and a pad (not shown) of a lead frame (f). Lead (not shown)
When the tip end side of the bonding wire a is brought into contact with the wires, the frictional heat generated is used to bond them together, thereby connecting the Mercedes-Benz F e + lead frame f. .

By the way, in the field of wire binding, it is required to increase the speed required for joining as much as possible in order to improve productivity.

However, with bonding methods such as those described above, which apply minute vibrations only to the side of wire A, there is a limit to the frictional energy caused by the vibrations, so the temperature rises slowly and the bonding time is inevitably long. However, the disadvantage is that the binding speed cannot be increased.Furthermore, if the bonding time is simply shortened, the desired bonding strength cannot be maintained, resulting in an extremely low yield υ. There is a demand for something that can increase binding speed while providing strength.

[Month of invention]

The present invention has been made in view of the above circumstances, and its purpose is to provide a wire bonding device that can improve the binding speed without degrading the quality of semiconductor devices.

[Summary of the invention]

That is, the present invention provides a work stage on which the Mercedes Benz Z and IJ frame is mounted with a vibration generating means that generates a lateral micro-vibration that is different from the micro-vibrations on the bonding wire side during bonding.
The frictional energy required for bonding is increased by the relative vibration between the bonding wire side and the work stage side, and the bonding is attempted to be achieved in a short period of time and on a wire that is lagging behind in bonding strength.

[Embodiments of the invention]

The present invention will be explained below based on an embodiment shown in FIG. FIG. 2 shows a wire bonding apparatus, and numeral 1 in the figure is a work stage.

The work stage 1 is composed of an XY work stage formed by stacking a table la that is movable in the X direction and a table 2b that is movable in the Y direction. Then, on the table la at the upper stage of this XY work stage, the pellets 2 . . . that constitute the entire semiconductor device and the lead frame 3 can be placed. Further, above the work stage 1, a bonding tool 4 is disposed which is driven up and down by a drive system (not shown). At the tip of this binding tool 4, a sonde wire 5 such as gold wire or aluminum wire fed out from a feeding section (not shown) is attached to the work stage 1.
The distal end side of the binding wire 5 is attached to the pellet 2 by the lifting and lowering movement of the bonding tool 4, and by a wire clamp mechanism (not shown).
pad (not shown), lead of lead frame 3 (
(not shown). An ultrasonic vibrator 6 is provided on the base side of the winding tool 4, and the ultrasonic vibrator 6 is attached to the winding wire 5 in a direction perpendicular to the axis of the winding wire 5.
For example, minute vibrations are applied to the work stage J along the X direction. On the other hand, linear motors 7h and 7b are connected to each table l a r 1 b constituting the workstation, and table 1! L
.

I b tx It is possible to drive in the X direction and the Y direction. Then, t! of each linear motor 7a, 7b! IIfi is an X-axis position scale 8&, a y-axis position school 8b1 that detects the movement of the table 1a (X direction) and the movement of the table zb (Y direction), respectively.
It is also controlled by the CPTJ 12 which outputs control signals to the linear motors 7a*7b based on the detection information of these position scales Ba and sb, and is controlled by the CPU.
Based on the butt positions of the pellets 2 . However, the movement of the work table 1 and the movement of the binding tool 4 ensure the operation necessary for wire bonding.

On the other hand, the CPU 12 has the function of guiding each position of the binding tool 4 and 12 and the lead frame 3, as well as the function of guiding each butt position of the pellet 2... and each lead position of the lead frame 3 of the binding tool 4. Each position scale 8 shows the position information when guided to the tip.
Drive information is programmed to cause the valley linear motors 7a, 7b to minutely vibrate in the movement direction (X direction, y direction) of each table lh, lb, received from the position scales 8a, 8b, linear motor 7,
．． 7b is used as a vibration generating means 13. However, during binding, the work stage 1 is given lateral micro-vibrations along the direction of the micro-vibration of the binding wire 4, and furthermore, lateral micro-vibrations different from the micro-vibrations of the binding wire 4. Then, effective frictional heat is generated by minute vibrations between the bonding wire 4 side and the work stage l side, which have substantially different phases in combination in two directions, and the binding is activated. It is now possible to do so. In addition,
Work stage l has a built-in heater (not shown), and pellets 2 cannot be heated to high temperatures...
Measures are taken to promote bonding by applying heat to the pearlets 2... and the lead frame 3 at a low temperature that does not affect the bonding.

Therefore, when bonding is performed using the wire bonding apparatus configured as described above, first the pellet 2 and the lead frame 3 are placed on the work stage 1.
are placed on the tower as shown in Figure 2. Next, CPU J
2 operates to output a command signal necessary for bonding to each linear motor 7a, 7b based on the butt position and lead position information input in advance. Accordingly, the work table 1 is driven at high speed, and first, one pellet 20 part is selected and the butt is guided to the tip of the binding tool 4. Then, the tip of the binding wire 4 is brought into contact with the butt at this position using the bonding tool 4. Here, the bending wire 4 is given minute vibration along the X direction by the ultrasonic vibrator 6, and on the work stage 1, each position scale aa, 8b indicates that the butt of the pellet 2 has been positioned as expected. The linear motors 7a and 7b are driven to generate minute vibrations based on the commands from the CPU I2, and minute vibrations are applied in the lateral directions of the X and Y directions. For this, pellet 2
At the contact portion between the binding wire 4 and the bonding wire 4, the frictional energy is dramatically increased due to the out-of-phase relative vibrations between the binding wire 4 side and the work stage l side, resulting in a large frictional heat p1. In this way, in contact areas where frictional energy is small and the temperature rise is slow, a quick temperature rise can be achieved by effective formation of frictional heat. This means that binding can be performed.

Then, once the /e Watt joining of this pellet 2 is completed,
Similarly, by driving the linear motors 7a and 7b, the leads of the lead frame 3 corresponding to the butt are guided to the tip of the bonding tool 4, and the tip of the binding wire 4 that is continuously fed out is guided to the binding wire 4.
Wire bonding is performed in which the wire roots 2 and the lead frame 3 are connected by binding using frictional heat generated by minute vibrations on the work stage 1 side and the work stage 1 side.

Then, all such wire bonding is performed between each butt of the pellet 2 and each lead of the lead frame 3, and then the bonding of another pellet 2 is performed.

Thus, bonding tools can be improved without reducing the quality of semiconductor products. Also,? At the time of binding, a heater (not shown) acts to heat the pellet 2 at a low temperature, so the effect can be further enhanced by using the heat generated by the heating in combination with the frictional heat.

In the above-mentioned embodiment, the work stage is given lateral micro-vibrations in both the same direction as the micro-vibration of the bonding wire and in different directions, so that the bonding wire side is affected by the combination of vibration directions. An example is given in which the micro-vibration is made different (different phase), but micro-vibration in one direction may be applied.

In this case, it goes without saying that the minute vibrations in the same direction have different frequencies (different phases) from the minute vibrations on the bonding wire side.

In addition, in the above-mentioned embodiment, the present invention was applied to a wire bonding apparatus that uses a movable work stage and a fixed bonding tool side, but the work stage is fixed and the binding tool side is fixed. Of course, the present invention can also be applied to a wire bonding apparatus which is movable using an XY table. That is, in this case, similar to the above embodiment, if a linear motor is used as a vibration generating means or an ultrasonic vibrator is used as a vibration generating means, and these are provided on the work stage, the same effect can be obtained.

〔Effect of the invention〕

As explained above, according to the present invention, the frictional energy required for bonding can be increased by the out-of-phase relative vibration between the bonding wire side and the work stage side, and the temperature increase which has been slow can be reduced. Wire bonding with excellent force and bonding strength can be achieved in a short time with increased agility.

Therefore, it is possible to improve the bonding tool without degrading the quality of the semiconductor device.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing a conventional wire bonding device;
FIG. 2 is a perspective view showing a wire binding device according to an embodiment of the present invention. 1...Work stage, 2...Bellet, 3...
Lead frame, 4... Bonding tool, 5...
- Bonding wire, 6... Ultrasonic vibrator, 7a. 7b... Linear motor, 13... Vibration generating means.

Claims (1)

[Claims] A minute vibration is applied to the bonding wire being fed out in a direction perpendicular to the axis of the bonding wire, and the tip side of the binding wire is brought into contact with the pellet and lead frame mounted on the work stage, and the frictional heat caused by the minute vibration is generated. The wire bonding apparatus is characterized in that, during bonding, a vibration generating means is provided on the work stage to generate a slight vibration in a lateral direction that is out of phase with the minute vibration on the bonding wire side. wire bonding equipment.