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Low temperature cofired 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 allow the integration of passive components, which leads to a high integration level. For microfluidic devices, the integration of 3D structures such as channels and chambers is necessary. Using LTCC will lead to integrating sensor elements due to high reliability, the good ceramic characteristics, and excellent physical properties. To realize 3D micro-channels beyond the laboratory, adequate manufacturing processes are essential. This study proposes the realization of microfluidic channels and shows in which ways these can be realized by a range of newly 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 microfluidic LTCC system will be shown based on a manufactured demonstrator. The final conclusion is that these established manufacturing and integration methods offer remarkable potential to meet the requirements for future circuit designs, where actual design concepts cannot solve all issues, in particular where harsh environmental conditions occur or a high integration concept is mandatory.

Three-dimensional interconnect devices are still strongly related to plastic materials. Since the use of these materials is limited in harsh environments, there is an application gap, which could be filled by ceramic circuit carriers. Low-temperature cofired ceramics (LTCC) offer promising solutions to fill this gap. This work provides a feasibility study, including the whole technological chain of ceramic multilayer processing. Targeting a curved multilayer substrate, fully equipped with SMD (Surface-mounted device) components, the particularities of single process steps are investigated. Two shaping methods based on quartz glass molds are compared with regard to shape fidelity and technological effort. The investigation of internal conductor lines and via connections reveals that the metallization should have a minimum width of 200 µm and the via diameter is limited to 150 µm. Further considerations focus on the possible footprint of components and use of cavities to increase the footprint of components. The limits of wire bonding on curved surfaces were inspected. Finally, the work presents a demonstrator of a fully equipped four-layer ceramic circuit, including internal wiring. Hence, the transfer of the 2.5-dimensional multilayer ceramic technology into the third dimension is proven.

No abstract

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.