A Piezoresistive Micro Pressure Sensor Fabricated by Commercial DPDM CMOS Process

A piezoresistive pressure sensor with a chip area of 2 mm 4 mm has been fabricated by a standard CMOS process with additional MEMS postprocess. The structure layers follow the design rules of the CMOS 0.8 m DPDM (Double-Polysilicon-Double-Metal) multiple-project-wafer foundry service provided by the Chip Implementation Center, Taiwan. We used a finite element method software ANSYS to analyze the mechanical behavior of the pressure sensor and used the commercial software CADENCE to design the structure layout. After the CMOS process and the MEMS postprocess, two CMOS pressure sensors with different diaphragm thickness were packaged and tested. The sensitivities of sensors were measured as 0.53 mV/atm/V and 13.1 mV/atm/V with non-linearity less than 5% (FSO), and agree with the theoretical prediction qualitatively.