Thermomechanical Related Failures in IGBT Based Power Converters

Østergaard, Lotte Haxen

4. term

Nanotechnology, Master

2014

2014-06-04

90 pages

I denne rapport er IGBT baserede effektkonvertere udsat for en accelereret test. Varmetransporten i effektmodulet er simuleret og viser at der er en cyklisk temperatur ændring under operation. Dette forårsager stress i grænsefladerne mellem de forskellige materialer, hvilket resulterer i termomekanisk relaterede fejlmekanismer. Nogle af disse fejlmekanismer undersøges i dette projekt. Topologien a metalliseringen på halvleder chipsene undersøges med skannende elektron mikroskopi og fokuseret ion stråle. Degraderingen i halvleder chipsene og wirerne studeres gennem elektriske målinger med fire-punkts probning. Kornstrukturen i wirerne er undersøgt med micro-sectioning. Disse metoder gør det muligt at kortlægge degraderingen i effektmodulet.

In the present work IGBT based power converters are subjected to an accelerated test. The heat transfer in the power module is simulated showing that a cyclic temperature change is present during power cycling. Stresses are thus induced at the interfaces between different materials, which causes thermomechanical related failures. Some of these failures are investigated in this project. The topology of the metallization on the semiconductor chips are examined using scanning electron microscopy (SEM) and focused ion beam (FIB) milling. The degradation of the semiconductor chips and the wires are examined through electrical measurements with four-point probing. A study of the grains structure of the wires is carried out using micro-sectioning. These methods enables degradation mapping of the power module.

Power electronics ; IGBT ; Failure ; Micro-sectioning ; Four-point probing

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