IGBT Modules - Technologies, Driver and Application (Second Edition) - page 86

Fig. 2.8
Construction of a standard IGBTmodulewith andwithout epoxy
2.3 Electrical bonding technology
There are two types of electrical bonding technology – internal and external. Internal
bonding technology refers to all electrical connections to semiconductors, while external
bonding technology refers to all the electrical connections between the component and
its environment. There is a further distinction, between load terminals and auxiliary
terminals such as the gate terminal, the auxiliary emitter terminal and the temperature
sensor connection.
Depending on the type of power semiconductor chip, the IGBT has at least three
contact points that are connected to its environment: The gate, themain emitter and the
collector. There are IGBT chips that also have an integrated "on-chip" temperature
measurement function or an "on-chip" current mirror. With these chips, the number of
connections rises with the additional functions. Since the IGBT chips that are used in
modern IGBTmodules have a vertical structure, the emitter and gate terminal is located
on theupper surface. The collector terminal is at thebottom.
The freewheeling diode required for the IGBT comprises anode and cathode, each of
which has solderable surfaces, so that, depending on the topology, either the anode or
the cathode canbe soldered to theDCB.
Regardless of the manufacturer, the power semiconductor chips in most series
production IGBT components are connected by soldering at the back and bond contact
at the front. The details of the manufacturing processes and, to some extent, the
materials chosen by themanufacturers vary, but theprinciples areessentially the same.
2.3.1 Internal connection technology
With internal connection technology, many factors besides the materials to be
connected come into consideration. These are dealt with in more detail below, in the
same order as theprocesses involved in constructing a standard IGBTmodule.
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