3D additive lithography for electronics towards highly integrated freeform structural electronics

Abstract

Electronics of the future-more tightly integrated with freeform 3D design-require rethinking the often bulky, planar design of current circuit boards. Significant size reduction compared to conventional PCBs can be made by working with bare die components over packaged SMDs, and by placing and interconnecting these dies in 3D space. To this end, TNO at Holst Centre has developed a novel multi-material additive manufacturing technique: "3D Additive Lithography for Electronics" (3D-ALE). By combining direct imaging lithography and 3D printing, this system is optimized for the production of electrically interconnected, heterogeneously integrated freeform functional devices. A scanning DMDbased light engine is used to pattern photopolymer and allows printing of electrical features down to 10 µm line spacings. Using industry-standard conductive pastes, electrical components can subsequently be integrated and interconnected within the printed polymer body. A microelectronic demonstrator to enable endoscopic ultrasound imaging via a catheter will be demonstrated. The device features sub-mm sized, bare die ASIC and CMUT chips integrated and interconnected using the 3D-ALE system.