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A method of using FEA software in direct calculation of the performance of MElMS pressure sensors is described. The pressure sensor is one of a family of MEMSpressure sensors, which use a piezo-resistor bridge on a silicon diaphragm as the transducer. The sensor model includes level-0 packaging and the geometry is parametric so that it can easily be applied to design variations. The method computes the resistunce of the piezo-resistors by calculating the piezo-resistance in each finite element. Then an accurate total resistance is calculated as a function of pressure and temperature, from which the transducer signal is estimated. The transducer signal is described in terms of the sensitivity, linearity and offset. The sensitivity matches the measured data within the one standard deviation of the measured' values. Deviation fiom linear is within 0.2% of the measured values. Not all of the signijkant factors that contribute to the offset have been included in this method.The use of an analytical solution as developed by Gong and Lee [2], is not possible. The resistor layout varies significantly from one design to the next. The variation in resistor location is necessary to balance the bridge. A balanced bridge has a constant total resistance as a function of pressure.

It is important to take into consideration the process-induced residual stress into reliability prediction modeling. Lack of process-induced stress may lead to error in reliability prediction. Therefore, careful investigation of the stress development is critical. In this paper, the stress development induced by ChipSeal® passivation process technology has been analyzed. The ChipSeal® passivation technology has been developed to enhance the reliability of commercially-off-the-shelf plastic encaptulated microelectronics component by sealing integrated circuit at the wafer level. The analysis takes every process step into account to investigate the temperature effect on the final residual stress. The section of the fabricated structure has been modeled in two different configurations. The stress developments have been simulated by numerical method, and the results have been analyzed to identify the critical location. Three different lengths of metal layer have been considered to investigate the effect of metal layer length structure. Finally, a response surface method is employed to determine the thickness effect of individual layers and to develop design guidelines to enhance ChipSeal® reliability.