Additive manufacturing of copper vertical interconnect accesses by laser processing

This paper introduces a new manufacturing process for vertical interconnect accesses (VIA). In contrast to industrially established VIA metallization technologies, the presented approach takes place without any chemical plating by combining copper ink and epoxy insulator coating with CO2 laser processing drilling sintering. The minimum resistances are less than 50 mΩ, fitting theoretically calculated value. A laboratory application scenario testing 10 × contact pad array pitch of 800 µm successfully demonstrates routing across five printed layers, including 128 blind 112 buried VIA.