Abstract
In the recent years, the rapid development of handheld devices which have become smaller, cheaper, and more functionalities. However, the MEMS accelerometer after packaging has presented many challenges such as residual stress and warpage. After the sensor device processing, there were many process uncertainties may cause changes in the resonance frequency and stiffness. These uncertainties can cause the performance of MEMS sensor unstable. Furthermore, the MEMS accelerometer sensor will be embedded in the LGA packaging and simulate the shrinkage of molding compound after molding. More details of packaging effect in device will be discussed in this research. In this research, the resonance frequency of the three-axis SOI accelerometer is successfully simulated by modal analysis, and also presents a simple compensation model for trimming the offset of capacitance differentiation using the measured resonance frequency. From the result, the accelerometer structural under high residual stress can cause the offset of capacitance differentiation. Furthermore, the sensitivities of the accelerometer are dropped significantly. By using the compensation model, the capacitance differentiation offset and the sensitivity are successfully trimmed. In addition, in order to investigate the packaging temperature effect on accelerometer structural (0-300⁰C), the LGA packaging 3D model was established. The results found that the sensitivity offsets of temperature effects are smaller than the offsets of residual stress effects, the residual stress effects will be a key factor affecting the sensitivity offsets.