Burn in Hours That Remove the Steepest Early Drift
Thermal burn-in under active electrical bias removes early non-linear drift, locking in long-term calibration stability before sensors reach the field.
Die Attach Epoxy Creep
Adhesive Migration
Time dependent displacement of cured adhesive layers destabilizes the mechanical mounting of integrated sensor dies. The onset of die attach epoxy creep occurs when thermo-mechanical stresses cause viscoelastic deformation in the underlying adhesive layer over time. This continuous micro-displacement alters the mechanical stress distribution across the silicon die, inducing spurious strain signals in sensitive transducer elements.
The scope of this phenomenon excludes outgassing contamination, focusing strictly on structural displacement within the adhesive bulk and interface.
Viscoelastic Deformation
Polymeric adhesives undergo slow shear deformation when exposed to sustained assembly stress or operational thermal gradients. Sustained temperature elevation reduces the storage modulus of the epoxy, allowing polymer chains to slide past one another under constant mechanical load. This micro-scale movement alters die tilt and alignment relative to the package base, modifying thermal dissipation paths and creating uneven mechanical stress across active sensor structures.
Over long storage periods, stress relaxation within the cured resin causes gradual baseline shift.
Sensor Displacement
Physical shift of the sensor die alters signal baseline stability and spatial orientation accuracy. When die attach epoxy creep progresses, mechanical strain transferred to piezoresistive or capacitive sensing elements produces persistent measurement offset.
Qualification Criterion
Reliability testing evaluates adhesive stability through high-temperature shear testing and optical coordinate measurement. Standardized qualification protocols mandate maximum allowable die displacement tolerances after extended thermal cycling. Component test certificates document post-stress alignment shifts to verify packaging stability.