Patent ID: 7589424

Claim:
A system, comprising: a microelectronic die having a first plurality of electrical contacts with a first pitch and having a first coefficient of thermal expansion; a substrate, having: a first major surface adjacent to the microelectronic die; a second major surface opposite the first major surface; a second plurality of electrical contacts with a second pitch about the equal to the first pitch on the first major surface electrically connected to the first plurality of electrical contacts of the microelectronic die; a base layer with a first side closer to the microelectronic die and a second side further from the microelectronic die; a plurality of build up layers on the second side of the base layer, the build up layers including metal traces separated by dielectric layers; a plurality of vias through the base layer to provide an electrical connection between the second plurality of electrical contacts and the metal traces; and a third plurality of electrical contacts at a boundary of the plurality of build up layers farthest from the base layer, the third plurality of contacts being electrically connected to the plurality of vias by the metal traces and having a third pitch greater than the first and second pitches; and a printed circuit board electrically connected to the third plurality of electrical contacts.