Inkjet printing approach to fabrication of non-sintered dielectric films and 3D structures

With the current explosive growth of information communication technologies, it is required to realize 3D system integration of hetero-materials such as organic and inorganic materials with multi-functionality based on irformation-, nano-, bio, and energy technology. The direct-writing by the inkjet printing has significant attention since it is feasible to pattern and fabricate fine features directly from design or image file. In this presentation, we have formulated ceramic suspension inks (AI ₂O₃ and BaTiO₃) and synthesized Ag conductive ink to print dielectric films and 3D circuitry such as metal-insulator-metal (MIM) capacitors and metal-via-metal interconnects. Inlg'et-printed dielectric films were prepared without high temperature sintering process. Instead, a polymer resin was infiltrated through the inkjet-printed ceramic films and cured at 280 °C. Since our goal is to fabricate non-sintered ceramic films, it is preferred that the inkjet-printed ceramic films should have a high packing density of more than 60%. High packing density leads to the inlg'et-printed worth better electrical and mechanical properties. Roughly about 40% of micro-voids inside the inkjet-printed ceramic films were filled with the resin. The dielectric property measurement of the inkjet-printed Al₂0 ₃-resin hybrid films indicated that dielectric constant and dielectric loss are 6 and 0.003, respectively at 1 MHz In the case of inkjet-printed BaTiO₃-resin films, their dielectric constant and dielectric loss at 1MHz are 75 and 0.009, respectively. And we could fabricate all inlg'et-printed embedded capacitor having MIM structure and daisy structure having metal- via-metal interconnection for 3D integration. The MIM capacitor consisted of 4 hybrid films that was placed Al₂O₃-Ag-Ba TiO₃-Ag hybrid layers in order from below. In daisy structure case, the conductor patterns of lower and upper layer were built up each other with the Al₂O₃ films, and micro via was formed by laser drilling process then filled with Ag paste for interconnection between the conductor patterns.