Micro Fluidic Mass Flow Sensor Concept for Functional Ceramic Circuits

Low temperature co-fired ceramics (LTCC) is established as a widespread platform for advanced functional ceramic circuits in many different applications, such as space, aviation, medical and sensor technology. MLC (Multi Layer Ceramics) based systems allows integrating passive components which leads to a high integration level. For micro fluidic devices the integration of 3D structures like channels and chambers are necessary. Using LTCC is predestined to integrate sensor elements due to the high reliability qualities, the good characteristics of the ceramic as well as the excellent physical properties. To realize 3D micro channels not only in lab status adequate manufacturing processes are mandatory. This study proposes the realization of micro fluidic channels and show in which ways these can be realized by a range of new developed manufacturing methods during the LTCC process. A benchmark of 3D laser structuring and two cold embossing technologies were investigated to show the benefits and also the limits of each technology. The sensor elements, which were directly integrated into the LTCC body, are based on PTC and resistor materials realized in thick film technology. The excellent performance of a micro fluidic LTCC system will be shown based on a manufactured demonstrator. The final conclusion is, that these established manufacturing and integration methods offer a remarkable potential to meet the requirements for future circuit designs, where actual design concepts cannot solve all issues satisfying, in particular where harsh environmental conditions occur or a high integration concept is mandatory.