Highly-sensitive flow sensor in LTCC

In this work we present a miniaturized gas flow sensor in Low Temperature Co-fired Ceramics (LTCC) based on hot-wire-anemometry. The newly developed LTCC fabrication process makes it possible to produce very thin freestanding heating structures within the ceramic showing a smaller power loss than actual state of art solutions. The new technological approach is the use of fugitive sacrificial material based on graphite preventing the free standing structures within the channel from sagging during the lamination and sintering steps. Furthermore we analyzed the influences of the sensor dimensions and the working temperature on the sensor performance in an analytic model and in a two dimensional Finite Element Model (FEM). At last the results of modeling and measurement are presented and discussed.