Report on the Development of a "Flip/Swith" Process for Completely 3D Printable Vertical Interconnects/Vias up to 60 GHz
Research Report Highlight
This research demonstrates 3D inkjet printing technology to develop fully-printed packaging solutions for wireless applications in the 60 GHz regime. Effects of surface energy, surface roughness, and physical topology gradients were explored.
This report outlines the development and convergence of inkjet printing technology with 3D stereolithography (SLA) printing processes with the goal to develop fully-printed packaging solutions for wireless applications in the 60 GHz regime. Inkjet printing has been demonstrated as an efficient technology for the patterning of planar (2D) and semi-planar (2.5D) topologies with conducting and insulating ink materials. In order to integrate this traditionally planar fabrication technology with truly 3D structures, several considerations are highlighted with respect to the 3D-printed SLA materials and structures: surface energy, surface roughness, and physical topology gradients (or slopes). The surface characteristics of these SLA-printed structures is essential for the development of fully-printed system-on-package (SoP) solutions, such as the application-specific fabrication of wireless IC and system encapsulations. Along with material properties for printability evaluation, processing guidelines between the two tooling platforms is discussed to provide insight into the state-of-the-art processes for multiplatform additive manufacturing. As a proof-of-concept demonstration, sloped interconnects are fabricated using inkjet and 3D printing to realize coplanar waveguide (CPW) transmission lines with physical slopes up to 65° and measurements up to 67 GHz.