Hybrid additive manufacturing based on vat photopolymerization and laser-activated selective metallization for three-dimensional conformal electronics

Abstract

Hybrid additive manufacturing technology (HAM) is a great advance of traditional additive manufacturing (AM) processes which enables the direct fabrication of full-functional end-use products rather than individual parts. Three-dimensional (3D) printed electronics is a representative product of HAM that could meet customized functional requirements of the industrial community such as consumer electronics, communication engineering, and automobile and aerospace industries. Herein, we propose a novel HAM technology that combines vat photopolymerization (VPP) 3D printing and the laser-activated electroless plating (ELP) process to fabricate conformal 3D printed electronics. A novel functional liquid photopolymer doped with 3 wt% of antimony tin oxide (ATO) and 1 wt% of titania (TiO2) nanoparticles is developed for this HAM technology. The 3D substrate can be successfully fabricated layer-by-layer with this functional photopolymer by a commercial desktop VPP 3D printer. A near-infrared (NIR) laser system selectively activates the surface of the 3D substrate and induces the SnII seeds for ELP. For 4-hour ELP, the thickness of plated copper layer approaches 11 µm and the electrical conductivity reaches 5.2 × 107 S/m which is close to pure copper (5.8 ×107 S/m). Finally, a selectively copper plated university badge is prepared to demonstrate the fabrication accuracy of the HAM technology, and a 3D conformal light-emitting diode (LED) circuit board is also developed to verify the feasibility of this HAM technology for customizing full-functional electronic products.