Multimaterial 3D Printing Technique for Electronic Circuitry Using Photopolymer and Selective Metallization

Herein, a 3D printing technique to enable the manufacturing of selectively plated polymer objects by photopolymer printing and copper metallization is presented. Metallized plastic has become popular in a number of industries due to its lightweight, flexibility of design, and cost-effective fabrication. Common metallization techniques require multiple pretreatment steps, such as surface etching, sensitization/activation, and acceleration. The proposed method, by eliminating the sensitization step, allows selective metallization of 3D-printed samples by direct plating. The method relies on the inclusion of silver seeds into a mixture of acrylate- and methacrylate-based monomers and oligomers, which enables direct electroless copper metallization following 3D printing. Ag(I) ions act as catalytic sites for copper deposition. Copper films grown with embedded 2 and 4 wt% Ag(I) seeds reach thicknesses of 5.7 ± 1.2 and 7.7 ± 1.3 μm, respectively. Furthermore, printing with pristine and silver-modified resins on the same sample allows selective plating: only the modified resin is plated leaving the pristine resin unaffected. A proof-of-concept temperature sensor is manufactured to demonstrate the performance of the printed interconnects.