Buried via in a circuit board

A method comprising:

• forming a plurality of multilayer cores, each of the plurality of multilayer cores comprising a sheet of cured dielectric material sandwiched between two metal wiring layers;
• embedding solder elements in a plurality of uncured dielectric layers, wherein a melting temperature of each of the solder elements matches a curing temperature of each of the uncured dielectric layers;
• alternately stacking the plurality of multilayer cores with the plurality of uncured dielectric layers, wherein each of the embedded solder elements are aligned with respective wire traces of the metal wiring layers of each of the uncured dielectric layers;
• and
• simultaneously melting the solder elements and curing the plurality of uncured dielectric layers by laminating the stacked plurality of multilayer cores with the plurality of uncured dielectric layers with a single lamination process and without using a laser heating step,
• wherein melting the solder elements and curing the plurality of uncured dielectric layers forms electrical connections between adjacent multilayer cores of the stacked plurality of multilayer cores and forms physical connections between the plurality of multilayer cores and the cured dielectric layers.

A method comprising:

• forming a plurality of multilayer cores, each of the plurality of multilayer cores comprising a sheet of cured dielectric material sandwiched between two metal wiring layers;
• embedding a solder element in an uncured dielectric layer;
• stacking the uncured dielectric layer between two of the plurality of multilayer cores, wherein the embedded solder element is aligned with wire traces of the metal wiring layers of each of the two of the plurality of multilayer cores;
• and
• simultaneously melting the solder element and curing the uncured dielectric layer by laminating the stacked uncured dielectric layer between the two of the plurality of multilayer cores with a single lamination process and without using a laser heating step,
• wherein melting the solder element and curing the uncured dielectric layer forms an electrical connection between the two multilayer cores and forms a physical connection between the two of the plurality of multilayer cores and the cured dielectric layer.