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This work reports the design and development of a MEMS based, piezoresistive sensor for micro-force measurement. Surface and bulk micromachining technology is employed to fabricate the force sensor from single crystal silicon wafer (i.e., no silicon on insulator wafer is used). Boron diffusion process combined with deep reactive ionic etching (DRIE) technique is used to form the side direction force sensors. The force sensor is integrated in a four arms structure MEMS gripper to experimentally verify the performance of the sensor. The resolution of the force sensor is in the micronewton range and, therefore, provides feedback of the forces that dominate the micromanipulation processes. Testing results show that the sensitivity of the piezoresistive sensors is better than 72V/N and the resolution is better than 3μN. Experimental show that it can successfully provide force sensing and play a main role in preventing damage of microparts in micromanipulation and microassembly tasks. [ABSTRACT FROM AUTHOR]

A vertical sidewall surface piezoresistor technology is developed for single-wafer-processed MEMS of in-plane lateral piezoresistors configuration. The technology based on the deep reactive ion etching (DRIE) and the ion implantation technology can be used to integrate piezoresistive sensor on the vertical sidewall of trench or beam easily. The developed technology has been successfully applied to a nano-positioning micro xy-stage integrated with displacement sensor based on the piezo-resistance effect, in which the piezoresistor has been fabricated on the vertical sidewall surface of the detecting beam to improve the displacement sensitivity and resolution of sensor. Besides satisfactory electric principles of the piezoresistors obtained, the experimental results also verify the sensitivity of the fabricated piezoresistive sensors is better than 0.903mV/μm without amplification, the linearity is better than 0.814%, which are well with design. [ABSTRACT FROM AUTHOR]