Design of a capacitive pressure sensor based on flip-chip packaging technology

This paper proposed a capacitive pressure sensor using flip-chip packaging technology to seal the vacuum cavity, and the sensing part is a variable capacitor with conductor/dielectric/conductor structure. Mechanical characteristics of the sensor were theoretically analyzed based on a composite membrane theory and evaluated by finite element analysis (FEA), showing that the difference of the model is within 8% compared to finite element analysis results. The back side flip-chip process can achieve wafer-level vacuum cavity packaging avoiding high voltage applied during conventional anodic bonding process and at the same time resolving the feed-through problem.