Localized high density substrate routing

A method of forming an apparatus comprising:

• forming a medium including low density interconnect routing therein;
• forming an interconnect element including first, second, and third layers of high density interconnect routing therein, the second layer of high density interconnect routing situated between the first and third layers of high density interconnect routing, the first, second, and third layers of high density interconnect routing including a plurality of electrically conductive members, an electrically conductive member of the plurality of electrically conductive members electrically connecting the first via to the second via;
• embedding the interconnect element in the medium;
• forming a dielectric layer over the interconnect element;
• forming first and second vias in the dielectric layer, the first and second vias passing through the dielectric layer;
• and
• forming solder resist over the dielectric layer, the solder resist not fully covering the first and second vias.

A method of forming a package comprising:

• forming an interconnect die including first, second, and third layers of high density interconnect routing therein, the second layer of high density interconnect routing situated between the first and third layers of high density interconnect routing, the high density interconnect routing including an electrically conductive member, the interconnect die including first and second electrically conductive pads, on or at least partially in, a top surface of the interconnect die, the electrically conductive member electrically connecting the first electrically conductive via to the second electrically conductive via through the first and second electrically conductive pads;
• connecting, by an adhesive material the interconnect die to a substrate, the substrate including low density interconnect routing therein;
• forming first and second electrically conductive vias in a dielectric layer of the substrate, the first and second electrically conductive vias electrically coupled to the first and second pads, respectively;
• and
• electrically coupling first and second dies to the first and second pads, respectively.