Abstract: The described embodiment relates generally to the field of PCB fabrication. More specifically conductive spheres are used in a bonding sheet to enable inter-layer communication in a multi-layer printed circuit board (PCB). The conductive spheres in the bonding sheet can be used in place of or in conjunction with conventional electroplated vias. This allows the following advantages in multi-layer PCB fabrication: dielectric substrate layers made of varying types of material; PCBs with higher resilience to stress and shock; and PCBs that are more flexible.