Patent ID: 8528203

Claim:
A method comprising the steps of: providing one or more insulator layers of a first type, wherein each of the one or more insulator layers of the first type comprises a spinel-based electrically non-conductive metal oxide distributed in an electrically non-conductive matrix material; registering the one or more insulator layers of the first type with respect to a positional control mechanism or system; irradiating the one or more insulator layers of the first type with laser radiation at one or more via formation locations where a conductive via is to be formed, wherein for each of the one or more insulator layers of the first type the laser radiation is sufficient to break down the spinel-based electrically non-conductive metal oxide and release metal nuclei at the one or more via formation locations completely through the insulator layer from a first surface of the insulator layer to a second surface of the insulator layer; providing one or more insulator layers of a second type, wherein each of the one or more insulator layers of the second type comprises an electrically non-conductive material without a spinel-based electrically non-conductive metal oxide distributed therein; stacking, aligning and laminating the one or more insulator layers of the first type irradiated in the irradiating step and the one or more insulator layers of the second type to form a substrate; drilling one or more through-holes in the substrate at the one or more via formation locations, wherein each of the one or more through-holes extends completely through the substrate from a first surface of the substrate to a second surface of the substrate, and wherein metal nuclei released at the one or more via formation locations in the one or more insulator layers of the first type during the irradiating step are exposed in the through-hole; electroless metal plating on the metal nuclei exposed in each of the one or more through-holes to form electroless metal only along the metal nuclei on each of the one or more through-holes.