The Hidden Stress

Electronic packages fail at interfaces — solder joints, die-substrate bonds, via connections. Standard design simulations check steady-state thermal stress: the package heats up, expands non-uniformly, and stress concentrates where materials with different thermal expansion coefficients meet. This analysis catches many failures. It misses the ones caused by the signals themselves.

A GPU-accelerated transient electromagnetic-thermal-mechanical co-simulation reveals signal-induced adiabatic stress — mechanical stress generated by rapid electromagnetic transients that heat the package too fast for heat to dissipate. Standard steady-state analysis averages over these transients. Homogenized models smooth over the fine-grained interfaces where the stress concentrates. Both miss what the full-scale transient solver reveals: failure mechanisms that exist only in the time domain, at spatial resolutions below the homogenization scale.

The through-claim: the three physics — electromagnetic, thermal, mechanical — are not separable at the design timescale. Standard workflows simulate them sequentially: compute the electromagnetic field, extract the thermal profile, calculate the stress. But signal bursts create thermal transients faster than the thermal simulation’s time resolution, and those transients create stresses that the mechanical simulation never sees. The failure mode is not in any single physics domain. It lives in the coupling between domains at timescales that sequential simulation cannot represent. Full co-simulation doesn’t add accuracy to an existing answer — it reveals phenomena that the separated analysis structurally cannot find.