A method of manufacturing at least a portion of a printed circuit board. The method includes: applying a lamination adhesive on a first plural-layer substrate that includes a plurality of circuit layers with at least one first metal pad on a first side of the first plural-layer substrate; applying a protective film on the lamination adhesive; forming at least one via into the lamination adhesive to expose the at least one metal pad on the first side of the first plural-layer substrate; filling at least one conductive paste into the at least one via formed in the lamination adhesive; removing the protective film to expose the lamination adhesive on the first plural-layer substrate; and attaching the first plural-layer substrate with a second plural-layer substrate that includes a plurality of circuit layers with at least one second metal pad on a second side of the second plural-layer substrate.