Figure 16. The hole diameter (H) is
typically 0.0005in. /13µm to 0.0008in. /20µm larger than the wire diameter.
Figure 17. A larger H dimension assists
with the flow of wire on high speed bonders. However, a small H dimension may be required
to produce small ball bonds and for more precise bond placement
Figure 18.
There can be many causes for wavy or sagging wires. Some of them are:
Excessive wire drag due to a
hole diameter being too small
Excessive wire drag due to the
inside chamfer being too small or damaged
Use of high elongation (soft)
wire
Use of too small of wire
diameter for the loop length desired
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