FEM assisted calibration of a MEMS-based dispensing system with integrated piezoresistive force sensors

The focus of this work is a liquid dispensing system relying on the use of piezoresistive silicon microcantilevers. The experimental calibration of newly developed devices, required for global characterization of their mechanical, electromechanical properties and other performance characteristics, is usually complicated due to the structures' small size as well as cost and time consumption. On the other hand, closed-form analytical solutions to the nonlinear behaviour of devices of non-canonical geometry incorporating residual stresses are not commonly available either. Therefore, virtual calibration by means of computational modelling and simulation is not only adequate but also highly desirable. The finite element method has repeatedly proven its worth as a useful and efficient technique for the investigation of various mechanical and multiphysical systems, and has been extensively used in the design and analysis of MEMS. In the present work, the method is employed for virtual calibration of mechanical and electromechanical properties of novel liquid dispensing cantilevers. Separately, mechanical and electromechanical simulation results are in good agreement with experiment. Combined, these simulation data provide the ultimate calibration tool, allowing control over the force applied by depositing devices onto the substrate, and thereby preventing stiction problems and damage of fragile depositing surfaces