A piezoresistive pressure sensor with a chip area of 2mm×4mm has been fabricated by a standard CMOS process with additional MEMS post- process. The structure layers follow the design rules of the CMOS 0.8μm 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 post- process, 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.
淡江理工學刊=Tamkang journal of science and engineering 8(1), pp.67-73