Analysis of Transient Thermal-Mechanical Stresses in Power Devices Using Test Chips and Optical Techniques

Inhalt:
Thermo-mechanical stress is one of the major failure mechanisms for power electronic devices. Therefore it is useful to determine such stresses prior to operation, in order to improve the reliability. In this work two techniques to determine these stresses time resolved are presented. A Silicon based self-heating test chip was developed. Using this chip simultaneous heating and stress measurement is possible. Digital Image Correlation was used as an optical approach with an IGBT. For both cases the stress development for active and passive heating was compared and dynamic measurement was performed.