Package Reliability

Packaging and interconnection technology deals with the reliability of power electronic components and systems with special consideration of effects caused by the integration of the semiconductor chip into the particular package.

Power Cycling

In application, power electronic systems are exposed to a wide variety of load profiles, which can cause irreversible effects. Depending on the selected application, such changes can only become noticeable after a considerable load period. Accelerated aging tests are used to investigate the effects of certain test parameters on the packaging and interconnection technology of a power semiconductor package to a reasonable extent. Based on the test parameters, which are derived from the corresponding application, quantitative and qualitative statements on the effects of innovations can ultimately be made with the help of life cycle models and continuously measured sensitive parameters.

D2Pak system during a power cycling test

There are numerous aspects to be considered when power cycling in order to achieve a high degree of reliability, reproducibility and thus comparability. These include these aspects:

Constant test conditions such as housing temperatures, supply voltages or load currents
Fast current control for flexible pulse patterns and shortest possible test durations
Reliable, flexible and sufficiently fast measurement technology
Automated recording of the parameters of each device under test to generate statistics and for quality assurance
Experience and a strong understanding of assembly and interconnection technology

A matured hardware and software backup concept also allows almost autonomous operation.

As different as the various power devices, their power classes and housing technologies are, so flexible must the test benches be. Accordingly, the Chair of Power Electronics has a wide range of different test benches, which have grown over the years and ultimately specialized for certain device groups and current classes.

Due to new semiconductor materials, more advanced package types and ever new fields of application for power electronic modules, the power cycling tests and their test benches are also undergoing constant development and subsequent quality validation.
In addition to classic power cycling tests, in which a device is or is not exposed to direct current, the professorship's repertoire also includes such tests in which the power dissipation is caused by active switching processes and deliberate overvoltage peaks. The know-how in test bench construction, programming of the software environment and finally the acquisition and evaluation of measured values has been developed in the course of the last years at the Chair of Power Electronics and advanced to a maturity which makes even internationally operating large companies in the field of power electronics our partners. Also in science, the investigations of the Chemnitz University of Technology in cooperation with various partners leave a lasting impression, which is supported by numerous publications.

Power cycling test bench of the latest generation

FEM Calculations

To determine the electrical, thermal and mechanical behaviour of power electronic devices with complex structures, systems consisting of differential equations are being solved and analysed through numerical methods.
The progressive development of semiconductor elements is requiring an increasingly accurate insight into power electronics systems, to examine the stress on single system components depending on electrical, thermal and mechanical parameters regarding increasing power density and efficiency. Empirical data gained in various measurements using different assembly and connection techniques and material combinations, allows the valuation of numerical determined results with regard to potential weak points in the system and explanation of associated failure pictures.

Heat development on the surface of a power semiconductor at given power cycling setup