Effect of Adhesive Materials on the Output Characteristics of Micro-Fused Silicon Strain Gauge Pressure Sensors

The performance and reliability of micro-fused silicon strain gauge (MSG) pressure sensor are critically influenced by thermal stress induced by environmental temperature fluctuations and thermal residual stress generated during the packaging process. The role of double-layer adhesive in modulating thermal stress distribution within the sensor remains insufficiently understood. This study employs finite element method (FEM) to systematically analyze the relationship between thermal stress and adhesive parameters, while evaluating the comparative efficacy of single-layer and double- layer glass frit in mitigating thermal stress and optimizing output performance. Results indicate that the maximum interfacial stress for the multi-layer structure (i.e., silicon strain gage-smaller CTE glass frit-larger CTE glass frit-stainless steel diaphragm) with gradient coefficient of thermal expansion (CTE) distribution using a double-layer glass frit as the adhesive was 35.6% lower than that of the single-layer glass frit configuration, while the zero-point output voltage of the sensor was reduced from 7.7 mV to 5.6 mV. The double-layer glass frit as the adhesive effectively mitigates thermal stress arising from the CTE mismatch between the silicon strain gauge and the stainless steel diaphragm. Furthermore, this configuration reduces the adverse effects of packaging-induced residual stress and thermal cycling on the sensor's output stability.