Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE credits
A controller with thermopile IR-sensors is developed to monitor and control the temperature of power electronics during active accelerated thermal fatigue tests - power cycling. Bond wiring is the dominating method for connecting semiconductors to the package leads, distance points on a chip or chip modules within a package. 25-30\% of all package related failures of electronic devices during their operation life time can be related to bond wire failures.
To test bond wires, power cycling test can be performed to stimulate failures in bond wire connections, enabling for further development and improvements in the area of bond wires. At IMTEK (Department for microsystems engineering) University of Freiburg, new types of aluminium/copper fibre-reinforced bond wires with a diameter 300 micrometers for power electronics are tested together with a power cycling equipment. During a power cycling test the component is periodically heated, with a current flow through the chip, and cooled down.
These new bond wires are bonded on IGBT (Insulated Gate Bipolar Transistor) modules. Since it is possible to measure the overall temperature (mean value) of the chip, using IR-sensors, the developed´controller in this final thesis is robust. Further, the implemented controller can easily be extended for power cycling with e.g. 10 modules in parallel.
2006. , 108 p.