LTCC and HTCC multilayer technology is used to manufacture miniaturized ceramic sensors and microcircuits. It is based on the structuring of ceramic films by means of punching and laser technology and their functionalization by means of mask-based printing processes, such as screen and stencil printing. These printing processes are established, reliable and enable high process throughput. However, in the case of low quantities or required flexibility in design, mask printing represents a significant disadvantage for cost and time reasons. In addition, the geometric freedom is limited to two-dimensional components and thus, the achievable degree of miniaturization.
Digital printing technologies, such as inkjet or aerosol jet, are a cost-effective alternative that can be used to produce small quantities and individualized products economically. These printing processes are completely additive and maskless, making them highly flexible. Comparatively large geometries, such as conductor tracks and contact pads, are printed using the inkjet process, while fine-scale areas (< 50 µm) are printed using the aerosol jet process. The combination of both printing technologies enables large-area and simultaneously precise structuring of multilayer ceramics on the one hand, and the creation of three-dimensional structures on the other.
A special feature are the dielectric ceramic inks based on LTCC, which replace conventional ceramic green films. Furthermore, sacrificial inks are used to implement self-supporting structures, such as membranes or webs. This increases the flexibility of the manufacturing process, the geometric degree of freedom and the achievable integration density. The challenge here is to adapt the materials and processes in terms of material compatibility and sintering-related shrinkage.