Laser-Activated Selective Electroless Plating on 3D Structures via Additive Manufacturing for Customized Electronics

This work proposes a facile and economical hybrid additive manufacturing (HAM)technology combining fused deposition modeling (FDM) 3D printing and laser-activated selective electroless plating (ELP) for fabricating full functional end-use 3D customized electronics. A functional acrylonitrile butadiene styrene (ABS) filament doped with dicopper hydroxide phosphate (Cu-2(OH)PO4) catalysts is developed for FDM 3D printing. The 3D printed structure is selectively laser-activated to generate Cu-I plating seeds on the ABS surface and then electrolessly plated. The poor surface finish, especially the layer lines, is an intrinsic defect of extrusion 3D printing, which not only affected the fabrication quality of the 3D substrates but also the electrical performance of the attached circuitry. Herein, a chemical polishing process based on acetone vapor is explored and characterized to significantly improve the surface quality and thereby the electrical performance of the attached copper layer. In this way, highly conductive metallic circuitry can be freeformly deposited and patterned on the 3D structure which is extremely attractive for customized 3D electronics. To show the application potential of this technology, a 3D conformal 555 timer astable oscillator circuit board and a hot-wire flowmeter are developed as demonstrators.