Enabling Additively Manufactured Electronics Through Laser Induced Graphene and Copper Deposition on Fully-Aromatic Polyimides

Abstract

Additively manufactured electronics (AME) have enabled the integration of electrical functionality into printed parts to form multifunctional components. Current AME approaches focus on hybridizing additive manufacturing (AM) with direct write technologies to integrate conductive traces into and onto printed geometries that are not possible through traditional electronics packaging processes. However, AME has been limited by 1) the poor thermal performance of printable substrates and their incompatibility with the requisite thermal post-processing of the conductive inks, 2) the poor dielectric performance of the printable substrates, and 3) the high resistivity of the printed conductive inks. To address these limitations, the authors demonstrate a process chain wherein conductive traces are selectively patterned onto fully-aromatic additively manufactured polyimides (AM-PI) via laser induced graphene (LIG) followed by electrodeposition of copper (Cu-LIG) to further lower the resistivity. In addition to characterizing process parameter effects on LIG conductivity and morphology, the resultant Cu-LIG resistivity, and the AM-PI/Cu-LIG interface, the process chain is validated through the fabrication and evaluation of 2D and 3D electronic components such as heaters, interdigitated capacitors, and a conformal antenna in Archimedes spiral geometry. Further, a 3D LED circuit is fabricated on a face-center cubic AM-PI lattice to demonstrate multi-planar circuit fabrication on geometrically complex 3D printed substrates.