JPH0523498B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a wire bonding method in a wire bonding apparatus, and particularly relates to wire loop control.

[Conventional technology]

Wire bonding involves forming a ball 3 at the tip of a wire 2 using an electrode 1 as shown in FIG. 4a, and then lowering the capillary 4 to place the ball on the semiconductor chip 5, which is the first bonding point, as shown in FIG. 4b. 3, move the capillary 4 as shown in FIG. 4c, and connect the wire 2 to the lead 6, which is the second bonding point. An example of a device that performs this work is
-Please refer to Publication No. 188839. Capillary 4 from the first bonding point to the second bonding point
The trajectory of wire loop control has a great influence on the quality of wire bonding. That is, unless an appropriate capillary trajectory is selected according to wire bonding conditions such as the bonding distance, the level difference between the semiconductor chip 5 and the leads 6, the shape of the leads, and the material of the wire, the results shown in FIGS. 4d and 4e
As shown in the figure, problems such as edge damage with the semiconductor chip 5 and leads 6 occur, and stress is applied to the wires to reduce the strength of the wires.

Therefore, various capillary trajectories have been proposed in the past. For example, the chevron-shaped capillary locus shown in Fig. 5 (see Japanese Patent Application Laid-Open No. 57-87143),
The arc-shaped capillary locus shown in the figure
220436), or a capillary trajectory in which when moving the capillary to the second bonding point, it passes through that point in the horizontal direction and then returns to the point (see JP-A-60-98634).
Each of them has advantages and disadvantages, and it is necessary to use them properly depending on the bonding conditions mentioned above.

[Problem that the invention seeks to solve]

Conventional wire bonding equipment needs to be equipped with many capillary trajectories according to each bonding condition as described above, and wires with XYZ-axis speed patterns and sequences are required to realize these capillary trajectories. Since a plurality of bonding methods must be used, the apparatus becomes complicated and there are problems in that it takes time to select the optimal method.

This invention was made to solve the above-mentioned problems, and an object thereof is to provide a wire bonding method that can easily realize various capillary trajectories.

[Means for solving problems]

The wire bonding method according to the present invention has the following advantages:
That is, the arrival timing of the capillary near the second bonding point in the Z direction and the XY direction is controlled by changing the acceleration.

[Effect]

The wire bonding method in this invention includes:
By controlling the arrival timing of the capillary in the Z direction and the XY direction near the second bonding point, it is possible to easily obtain a capillary trajectory that is suitable for various wire bonding conditions, increasing the reliability and productivity of wire bonding. will improve.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. As shown in FIG. 1, when moving the capillary 4 from the first bonding point A to the second bonding point B, which is a bonding distance L, the XY Control direction and arrival timing in Z direction. Three aspects of the control are shown in FIG. In the figure, 7 is the velocity waveform of the capillary 4 in the XY direction, and 8, 8', 8'' are the velocity waveforms in the Z direction. When the XY and Z directions arrive at the same time, Figure 2c shows the case where the XY direction arrives first.In addition, in both cases of this example, the capillary rises in the Z direction by half the amount of rise. It starts in the XY direction.Also, the third a
Figures 2a through 3c show the locus of the capillary 4 when it moves with the velocity waveforms shown in Figures 2a through 2c.

As you can see, the capillary 4 is
It moves in the directions with a uniform acceleration waveform, keeping the waveform in the XY direction constant and changing the waveform in the Z direction. With such wire bonding control, the wire is pulled sideways by a distance s in front of the second bonding point in a nearly triangular trajectory as shown in Figure 3a, so the wire loop is deflected and the loop height is relatively low. It is easy to achieve anything from a wire loop shape to a wire loop shape with a locus close to a rectangle as shown in FIG. The reliability and productivity of wire bonding can be improved.

Of course, it is possible to program an electronic control device such as a computer to select the arrival point of the movement in the X and Y directions with respect to the upper vicinity C of the second bonding point, and set the above three modes arbitrarily using an appropriate selection button, etc. It goes without saying that the method of the present invention can be carried out in any way possible.

In the above embodiment, the acceleration/deceleration of the capillary 4 in the Z direction was changed, but as shown in Fig. 2b, the waveform in the Z direction was kept constant and the waveform in the Good too.

Further, in the above embodiment, the case where the capillary 4 is moved at constant acceleration/deceleration was explained, but any speed waveform may be used as long as it is within the scope of the present invention to control the timing of arrival at the upper vicinity C of the second bonding point. You can move it.

〔Effect of the invention〕

As described above, by changing the inclination of the basic velocity pattern in the XY and Z directions, that is, the acceleration, and controlling the arrival timing in the XY and Z directions near the second bonding point of the capillary, various types of bonding can be achieved. A capillary trajectory suitable for the conditions can be easily obtained, improving the reliability and productivity of wire bonding.

[Brief explanation of drawings]

Fig. 1 is a model diagram of a wire bonding method according to an embodiment of the present invention, Fig. 2 is a diagram showing a capillary velocity waveform, Fig. 3 is a diagram showing a capillary trajectory, and Fig. 4 is a model showing wire bonding. 5 and 6 are diagrams showing conventional capillary trajectories. In the figure, 2 is a wire, 4 is a capillary, and 5 is a wire.
6 indicates a semiconductor chip, and 6 indicates a lead. In addition, in the figure,
The same reference numerals indicate the same or equivalent parts.

Claims (1)

[Claims] 1. On a table that can be moved in the XY directions,
In wire bonding, in which the wire is connected between two points using a capillary through which a wire penetrates and is movable in the Z direction, after the wire is connected to the first bonding point, the capillary moves in the Z direction to connect the wire. When moving in the XY direction toward the second bonding point while
A wire bonding method characterized by controlling the arrival timing of the capillary in the Z direction and the XY direction near the bonding point.