Fully Integrated Bridge-Type Anemometer in LTCC-Based Microfluidic Systems
A thick film anemometer for in situ control of the flow rate in fluidic systems was designed, manufactured and characterized. The sensor is integrated in a retention modulus consisting of Low Temperature Cofired Ceramics (LTCC). These materials allow the cost-effective realisation of fluidic microsystems with integrated electronics. The challenge of the work is to design an anemometer under the exclusive use of thick film technologies. The necessity to trim resistors causes the external use of relevant pastes. Therefore, the use inside of a closed fluidic system requires the leak of process gases and, at the same time, a maximal heat-insulating of the sensor element from the substrate. Free-standing elements necessitate the control of stress due to shrinking mismatch, TCE mismatch, density gradients and deformation during the lamination. In the presented solution, embossed flue channels prevent blow forming on a free-standing bridge. The anemometer has a linear sensor characteristic for flow rates up to 0.1 ml/min. The layout guarantees that the fluid gets only in contact with the basic ceramic material, which is compatible with a wide range of biological substances. Therefore the sensor is applicable in contact with cell fluids or PCRreagents.
Pietro VINCENZINI and Giuseppe D'ARRIGO
H. Bartsch de Torres et al., "Fully Integrated Bridge-Type Anemometer in LTCC-Based Microfluidic Systems", Advances in Science and Technology, Vol. 54, pp. 401-404, 2008