Stacked semiconductor die assemblies with substrate heat sinks and associated systems and methods

A substrate, comprising:

• a first side including contact pads and a plurality of substrate bond pads, wherein the contact pads are configured to directly attach to a controller die and individual substrate bond pads are configured to couple with corresponding die bond pads of a memory die through bonding wires;
• and
• a second side, opposite to the first side, including a heat sink configured to transfer heat from the controller die to a thermally conductive pad of a printed circuit board (PCB) and a plurality of interconnect pads for external communication between the PCB and the controller die and/or the memory die, wherein:
• the heat sink occupies an area of the second side at least twice an area of any of the interconnect pads,
• the heat sink has an inner surface facing the first side, and
• each of the plurality of interconnect pads has an inner surface facing the first side and coplanar with the inner surface of the heat sink.

A semiconductor system, comprising:

• a semiconductor die assembly, including:
• a substrate having a first side and a second side opposite to the first side;
• one or more memory dies disposed over the first side of the substrate;
• a controller die attached to the first side of the substrate and operatively coupled with the one or more memory dies;
• interconnect pads at the second side of the substrate, operatively coupled with the controller die and the one or more memory dies;
• and
• a heat sink at the second side of the substrate, the heat sink covering an area of the second side at least twice an area of any of the interconnect pads,
• wherein the heat sink has an inner surface facing the first side, and
• wherein each of the plurality of interconnect pads has an inner surface facing the first side and coplanar with the inner surface of the heat sink;
• and
• a printed circuit board (PCB) carrying the semiconductor die assembly, wherein the heat sink of the semiconductor die assembly is coupled with a thermally conductive pad of the PCB.