Simulations for thermal warpage and pressure nonlinearity of monolithic CMOS pressure sensors

The operation function of a piezoresistive pressure sensor utilizes a voltage output to detect the magnitude of pressure. In addition to the bipolar process, the complementary metal oxide semiconductor (CMOS) process has been used in the pressure sensor applications with the evolution of semiconductor industry. The basic design concept for monolithic pressure sensors is to fabricate a standard submicron CMOS process with appropriate modifications to integrate on-chip signal conditioning circuits. with anisotropic-etched piezoresistive sensing elements. In this study, thermal stress simulations with applied pressure loadings are used to estimate the electromechanical behavior of a new monolithic sensing element concept design. The major tasks are to predict the ripple deformation of a silicon diaphragm due to the thermal residual stresses from multiple passivation layers and estimate the pressure nonlinearities on the transducer. More detailed approaches with design and performance concerns are also discussed.