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蔣鎧宇 (Kai-Yu Jiang)
蔣鎧宇 (Kai-Yu Jiang)
Development of a Polysilicon-based Capacitive Micro Accelerometer
Development of a Polysilicon-based Capacitive Micro Accelerometer
多晶矽電容式微加速規的研發
多晶矽電容式微加速規的研發
In this study, employing the polysilicon-based CMOS process, the related technique of design, fabrication, and measurement are built up to develop CMOS-MEMS capacitive accelerometer which integrate sensing circuit and MEMS structure to achieve batch fabrication.
In this study, employing the polysilicon-based CMOS process, the related technique of design, fabrication, and measurement are built up to develop CMOS-MEMS capacitive accelerometer which integrate sensing circuit and MEMS structure to achieve batch fabrication.
For the design of micro accelerometer, differential-pair sensing finger with gap-closing type is used to reduce the coupling effect; and a novel symmetric layout of suspension is proposed to eliminate the mismatch of spring constants in X and Y axes resulted from size deviation during fabrication, which would simplify the sensing circuit design. Furthermore, through the commercial finite-element-analysis (FEA) software ANSYSR, performances of micro accelerometer including stiffness, residual stress, self-test micro-actuator, and operation bandwidth are simulated and discussed for further verification. In order to achieve high sensitivity of micro accelerometer in the constrained die-area, the sizes of sensing fingers are optimized, and the performance shows that sensitivities of micro accelerometers with single axis design and two axes design can reach to 0.85 fF/G and 1.7 fF/G, respectively.
For the design of micro accelerometer, differential-pair sensing finger with gap-closing type is used to reduce the coupling effect; and a novel symmetric layout of suspension is proposed to eliminate the mismatch of spring constants in X and Y axes resulted from size deviation during fabrication, which would simplify the sensing circuit design. Furthermore, through the commercial finite-element-analysis (FEA) software ANSYSR, performances of micro accelerometer including stiffness, residual stress, self-test micro-actuator, and operation bandwidth are simulated and discussed for further verification. In order to achieve high sensitivity of micro accelerometer in the constrained die-area, the sizes of sensing fingers are optimized, and the performance shows that sensitivities of micro accelerometers with single axis design and two axes design can reach to 0.85 fF/G and 1.7 fF/G, respectively.
For the fabrication of micro accelerometer, the residual stress of polysilicon structure that affects the deflection of sensing fingers is adjusted successfully by annealing process, and the database of the correlation between residual stress and annealing process is built up. Furthermore, an anti-stiction design rule is established successfully by finger test key to solve the severe stiction problem.
For the fabrication of micro accelerometer, the residual stress of polysilicon structure that affects the deflection of sensing fingers is adjusted successfully by annealing process, and the database of the correlation between residual stress and annealing process is built up. Furthermore, an anti-stiction design rule is established successfully by finger test key to solve the severe stiction problem.
For the measurement of micro accelerometer, scanning electron microscope (SEM, NCTU) and 3D profiler (ET-4000, NCTU) are used to determine the practical geometric sizes of fabricated accelerometers. The optical profiler (white-light interferometer, CIC) and MEMS motion analyzer (MMA, CIC) are used to characterize the deflection of sensing fingers and the dynamic response of accelerometers, respectively.
For the measurement of micro accelerometer, scanning electron microscope (SEM, NCTU) and 3D profiler (ET-4000, NCTU) are used to determine the practical geometric sizes of fabricated accelerometers. The optical profiler (white-light interferometer, CIC) and MEMS motion analyzer (MMA, CIC) are used to characterize the deflection of sensing fingers and the dynamic response of accelerometers, respectively.
[1] K.-Y. Jiang, H.-L. Chen, W. Hsu, Y.-K. Lee, Y.-W. Miao, Y.-C. Shieh, and C.-Y. Hung (October 2012). A Novel Suspension Design for MEMS Sensing Device to Eliminate Planar Spring Constants Mismatch. The 11th IEEE Conference on Sensors, Taipei, Taiwan.
[1] K.-Y. Jiang, H.-L. Chen, W. Hsu, Y.-K. Lee, Y.-W. Miao, Y.-C. Shieh, and C.-Y. Hung (October 2012). A Novel Suspension Design for MEMS Sensing Device to Eliminate Planar Spring Constants Mismatch. The 11th IEEE Conference on Sensors, Taipei, Taiwan.
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