Enabling 3D multilayer electronics through the hybrid of vat photopolymerization and laser-activated selective metallization

Mass customization of three-dimensional (3D) electronics is a state-of-the-art production paradigm aiming to deliver on-demand products with complex shapes and bespoke functionalities drives to satisfy specific requirements. However, traditional techniques such as printed circuit boards (PCBs) can only deliver 2D/2.5D electronics with regular geometry and are extremely costly for custom manufacturing. Hybrid additive manufacturing (HAM) technology has been regarded as a competitive alternative for customizing 3D electronics. Herein, we propose a series of strategies to exploit the potential of the HAM technology that combines vat photopolymerization (VPP) 3D printing and the laser-activated electroless plating (ELP) process for fabricating embedded 3D multilayer electronics. Digital light processing (DLP), a type of VPP 3D printing, is adopted to build the 3D matrix due to its thick layer curing capability which is highly preferable for electrical circuitry embedment. Copper layer is deposited on the 3D matrix via laser-activated ELP, which provides an extreme high conductive of 5.2 × 107 S/m close to pure copper (5.8 × 107 S/m). Two strategies, cavity way and chamber way are proposed for embedding various electronic components within the 3D matrix, furthermore, internal and external vertical interconnection methods are implemented for the vertical wirings between different electronic circuitry layers. Eventually, a pyramid-shaped LED blinking system with 3 embedded circuitry layers and a lighting model of the auditorium at Southeast University are developed to verify the feasibility of this HAM technology, which show great application potential to deliver customized 3D electronic products for consumer electronics, communication, medical devices, aviation and aerospace industries.