On an IGBT chip, both the emitter and the gate are at the front. The number of bond
wires depends on the actual value of the current I
. This is determined by the
electrical and thermal resistance of the bond wire
. This is calculated from the length
and diameter of the bond wires and the sum of all the bond wires. The highest
temperatures are reached in themiddle of a bond wire, compared to the beginning and
end parts, which are joined to the chip, theDCB or the frame, and therefore have better
cooling. Since the bond wire is embedded in silicone gel, this determines themaximum
temperature that can be reached in thebondingwire.
Exampleof aluminium frame bonding
The frame bondconnects theDCB substratewith theelectrical connection located in the
plastic case through a process similar to chip-DCB bonding in which, after soldering of
the chip and the chip bonding process and, if necessary, baseplate soldering, the
electrical connection in the plastic frame is electrically joined to the DCB via the heavy-
wire bonding process.
Simulated result of framebondingwithaluminiumand copper wires
The specific electrical resistance e.g.
mm 0264 .0
applies for aluminium bond wires; for copper, it is
mm 0178 .0