Semiconductor package and method of making the same
View Patent ↗The present invention relates to semiconductor devices comprising two or more dies stacked vertically on top of one another, and methods of making the semiconductor devices. The methods may comprise a combination of wafer-level through silicon interconnect fabrication and wafer-level assembly processes.
1. A semiconductor package comprising:
a substrate;
a first die having a front side, a back side, and a plurality of through silicon interconnects, the first die being stacked onto the substrate; and
a second die having a front side, a back side, and a first plurality of conductive bumps formed at the back side of the second die, the second die being stacked onto the first die and having under-filled the first plurality of conductive bumps such that the first plurality of conductive bumps electrically communicate with the through silicon interconnects;
wherein a first mold material encapsulates the second die and the front side of the first die; and
a second mold material encapsulates the first die, the second die, and a plurality of solder interconnects.
2. The semiconductor package of claim 1 , wherein each of the through silicon interconnects further comprises:
an end portion at the back side of the first die and a top portion at the front side of the first die;
a dielectric layer formed along internal walls of the through silicon interconnect;
a barrier metal layer formed over the dielectric layer;
a seed layer formed over the barrier metal layer; and
a metallic material filling space within the internal walls of the through silicon interconnect.
3. The semiconductor package of claim 2 , further comprising:
a metallic layer and a passivation layer formed on the front side of the first die so as to be non-overlapping;
a metallic layer and a passivation layer formed on the back side of the first die so as to be non-overlapping;
a plurality of under bump metallization (UBM) pads formed on the metallic layer on the back side of the first die; and
a second plurality of conductive bumps formed on the UBM pads.