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.