Hybrid microelectronic substrate and methods for fabricating the same

A method of forming a hybrid microelectronic substrate, comprising:

• forming a high density microelectronic patch substrate having a first surface, an opposing second surface, and at least one side, wherein the high density microelectronic patch substrate comprises a plurality of dielectric layers and a plurality of conductive routes;
• aligning the first surface of the high density microelectronic patch substrate on a panel;
• disposing a first dielectric material layer over the high density microelectronic patch substrate, wherein the first dielectric material layer contacts at least one dielectric layer of the plurality of dielectric layer of the high density microelectronic patch substrate at the second surface thereof and contacts the at least one side of the high density microelectronic patch substrate;
• forming at least one additional dielectric material layer over the first dielectric material layer;
• forming at least one conductive route within the first dielectric material layer and the at least one additional dielectric material layer, wherein the first dielectric material, the at least one additional dielectric material layer, and the at least one conductive route within the first dielectric layer and the at least one addition dielectric material comprise a lower density microelectronic substrate and wherein the lower density microelectronic substrate includes at least one contact pad formed in or on an outer surface of an uppermost dielectric material layer of the at least one additional dielectric material layer, and wherein the at least one top contact pad is in electrical contact with at least one conductive route of the plurality of conductive routes within the lower density microelectronic substrate;
• and
• forming at least one electrical contact through a portion of the first dielectric material layer to electrical connect the at least one conductive route of the lower density microelectronic substrate to the high density microelectronic patch substrate.