etching inner metal layers on both sides of an insulating core to form patterned interconnect on the inner metal layers;

laminating a component metal sheet and a component insulator layer over one of the inner metal layers;

laminating a pad metal sheet and a sacrificial insulator layer over another one of the inner metal layers;

etching the component metal sheet to form patterned component-layer interconnect from the component metal sheet;

etching a pad metal layer of the pad metal sheet to form solder pads from the pad metal sheet;

drilling castellation vias on the pad metal layer, and forming metal inside the castellation vias that connect the pad metal layer to the patterned component-layer interconnect or the patterned interconnect on the inner metal layers;

milling a cavity into the sacrificial insulator layer, the cavity not reaching the patterned interconnect on the inner metal layers; and

wherein the sacrificial insulator layer covered by the solder pads forms a plurality of stand-offs after milling,

whereby the solder pads on the stand-offs are surface-mountable to a main board.