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A piezoresistive pressure sensor with the electrostatic self-detecting structure was developed in the paper, which can solve the issue of low efficiency and time-consuming drawbacks of the traditional method in testing and calibrating the sensor with the specialized equipment. The theoretical model of the composite membrane piezoresistive sensor was established, the analytical model of the electrostatic force driven by an electrostatic voltage was obtained, a feasible fabrication process based on flip-chip process was proposed based on the MEMS processing, the pressure sensor and its detection structure were manufactured to verify the validity of the model in the paper. From the experiment results, it can be verified that the sensitivity of the pressure sensor was 1.77 mV/hPa and the non-linearity was 1.19% respectively. At the same time, the electrostatic force used to test sensor calibration could replace the loaded pressure in the range between 110 and 500 hPa. [ABSTRACT FROM AUTHOR]

Abstract: Wafer level thin film residual stress is generally determined by a full-field optical method, which converts the measured curvatures into the stress using Stoney formula. During the fabrication of the IC and MEMS devices, however, multilayered thin films are often generated on both sides of the wafer simultaneously. By extending the Stoney formula, this paper presents a method for measuring residual stress in the multilayered films on the wafer. In the method, only the back film layers of the wafer need to be etched in turn and corresponding curvature radii is measured by the full-field optical method. The residual stress of each film layer may then be obtained by the radii using the extended Stoney formula. By comparing the proposed method with the existing method using the traditional Stoney formula, it is shown that the proposed method is more simple and economical for practical applications. The extended Stoney formula was verified by Coventorware. Experiments show that the proposed method is simple and accurate for process monitoring. [Copyright &y& Elsevier]

A novel micromachined pressure sensor is reported. The sensor works based on the Hall effect. The structure and fabrication process of this sensor are presented. During measurement, the applied pressure changes from 30 to 110 kPa. Test results show that the output Hall voltage of the sensor increases linearly with the pressure applied on the membrane and the sensitivity is 22.8 µV/hPa. Furthermore, it is found that the output voltage is composed of two parts: the Hall voltage and the offset voltage. The offset voltage also changes with the applied pressure, but is much smaller than the Hall voltage. [ABSTRACT FROM AUTHOR]