wire bonding and flip-chip bonding

Wire bonding is the technique of using thin wire and a combination of heat,
pressure, and/or ultrasonic energy to make the interconnection between the
die and package. The wires are made of gold, aluminum, or copper. Wire diameters
start at 15
m and may increase to several hundred micrometers for
high-powered applications. There are two main classes of wire bonding:
ball bonding and wedge bonding. In both types, the wire is attached at the
ends using some combination of heat, pressure, and ultrasonic energy to
make a weld.

Wire bonding is generally considered the most cost-effective technology,
and it is currently used to assemble the vast majority of semiconductor