Modelling Impact of Viscoelastic Properties of Die-Attach Material on the Bias Response of Resonant Inertial Sensors

The method discussed in this paper is based on the viscoelastic-induced bias of a resonant accelerometer due to polymer-based die attach material. Based on a new physical model, the residual bias of two identical accelerometer designs employing two different polymer die-attach materials are compared in the temperature range of -40°C to +40°C. A description of the physical model is provided considering the packaging geometry and viscoelastic properties of the polymer die-attach material. The model results are compared to the bias response of two resonant accelerometers for an equivalent package. The comparison highlights the differences in the mechanical properties of the polymer materials over the temperature range and predicts a gain by using the adhesive with the most advantageous properties.