LOW- AND HIGH-TEMPERATURE SILICON WAFER DIRECT BONDING FOR MICROMACHINED ABSOLUTE PRESSURE SENSORS

摘要

In this paper high- and low-temperature silicon-to-silicon direct bonding processes for the fabrication of absolute pressure sensors are presented. Using high temperature bonding, wafer stacks can be pre-processed, where thin membranes seal shallow cavities. A CMOS-like process is then used to create the piezoresistors on these substrates. Alternatively, a low temperature bond process can be used to seal the backside cavity of bulk micromachined pressure sensors. Both methods were used to fabricate absolute pressure sensors. State-of-the-art performance and high process yield was achieved.