A high sensitivity force sensor for microassembly: design and experiments

This paper aims at advancing micromanipulation technology with in-situ PVDF piezoelectric force sensing during microassembly and packaging process. To allow close monitoring of magnitude and direction of forces (adhesion, surface tension, friction, and assembly force) acting on micro devices during manipulation, the polyvinylidene fluoride (PVDF) is used to fabricate highly sensitive 1-D and 2-D sensors for assembly of micro devices. By using an electronic circuit designed with the effective data processing techniques, the contact/impact force signal can be obtained desirably and then is fed back for improving the reliability of assembly. The calibration of the sensor has been conducted on a high precision optical microscope system with the optimal image processing methods. Preliminary calibration results verify the effectiveness of the sensor model with high sensitivity as well as a resolution in the range of sub-μN. Furthermore, experiments demonstrate the performance of the force sensing system. Ultimately the technology will provide a critical and major step towards the development of automated manufacturing processes for batch assembly of micro devices.