Cracking explained: Thermal path analysis in high-power multi-chip modules

This technical study demonstrates how thermal impedance measurement using advanced hardware effectively characterizes heat conduction paths in power semiconductor packages. Through structure function analysis, engineers can now detect and quantify structural defects non-destructively, correlating thermal resistance changes with actual crack propagation.

Degradation of thermal conduction paths represents one of the most critical failure mechanisms in power semiconductor packages. This comprehensive analysis examines how solder fatigue, caused by thermo-mechanical stresses at interfacing contacts, leads to cracking and thermal performance deterioration. Using advanced hardware, researchers have established a clear correlation between thermal measurements and physical degradation.

Key findings:

• Junction-to-case thermal resistance (Rthjc) directly correlates with crack propagation
• K-value shows linear relationship with cross-sectional attached area
• Structure functions provide non-destructive evaluation capability
• Individual chip analysis possible within multi-chip modules
• Validated results through scanning acoustic microscopy