ACCELERATED QUALIFICATION OF HIGHLY RELIABLE POWER MODULES
Power cycling under thermal overload
Highly reliable interconnect technologies are increasingly used to achieve much higher reliability or enable the device to operate at elevated temperature. These benefits, however, evolve new challenges for the qualification process.
Highly reliable interconnects of an IGBT have been tested by power cycling. The test has been successfully accelerated by exceeding the specified operating conditions of the device. The approach is suitable to reduce the test time from several months to one day without changing the underlying failure mechanism, as revealed by experimental results and failure analysis.
Additionally, a lifetime model is derived and compared to yet published models, revealing that the lifetime of modern power modules is much less affected by high temperatures, in particular when advanced interconnect technologies like silver-sintering are applied. Limitations and application examples are discussed as well. The full paper contains:
- Approach for an accelerated qualification procedure,
- Description of the device under test,
- DC-DC conversion systems,
- Comparative discussion of power cycling results of highly reliable engineering samples and commercial devices, and
- A simplified lifetime model and comparison to yet published models.
First publication of the paper at PCIM Europe Digital Days 2021.
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