Model validity at High temperature

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Model validity at High temperature
Hello, I have seen in the FIDES guide that your models are valid between -55C and 125C. Do you think there will be a high mismatch of activation energy at 175C or 200C ? Some new failures mechanism will appear at high temp? an other question : only Epoxy PCB are treated in the guide? Polyimide boards are not included ? thanks and regards
Re: Model validity at High temperature

About temperature:
We have no or very few information about failure rates or failure mechanisms above 125°C. It it possible that activation energy increase with temperature as new failure mechanism becomes possibles. It is also possible that usual failure mechanism becomes so predominant at very high temperature that new ones are not significant...
Therefore sorry, I can′t help you much.

About PCB materials:
No, only FR4 covered in the FIDES Guide. I would have been too much work to cover all PCB materials. You can find data about relative CTE and their influence in the RDF2000 (UTE C 80-810), but it is not easy to use in reliability prediction. Note that in the hybrid &MCM chapter of the FIDES Guide 2009, the ceramic substrate are also covered.