Stacked semiconductor die assemblies with thermal spacers and associated systems and methods

A semiconductor die assembly, comprising:

• a thermally conductive casing, wherein the thermally conductive casing defines a cavity;
• a stack of first semiconductor dies within the cavity;
• a second semiconductor die mechanically and electrically coupled to the stack of first dies;
• a package substrate carrying the second semiconductor die;
• and
• a thermal spacer disposed between the package substrate and the thermally conductive casing, wherein the thermal spacer includes a semiconductor substrate and plurality of conductive vias extending through the semiconductor substrate and electrically coupled to the stack of first semiconductor dies, the second semiconductor die, and the package substrate;
• wherein the stack of first semiconductor dies has a first footprint;
• wherein the second semiconductor die has a second footprint larger than the first footprint, wherein the second semiconductor die has a peripheral region extending laterally outward with respect to the stack of first semiconductor dies;
• wherein the thermal spacer has a third footprint that is at least as large as the first footprint along at least one axis, but no larger than the second footprint along the at least one axis.

A semiconductor die assembly, comprising:

• a logic die having a face;
• a memory die stacked relative to the logic die;
• a thermally conductive casing extending at least partially around the memory die and at least partially enclosing the memory die within an enclosure, wherein the thermally conductive casing has a sidewall attached directly to the face of the logic die by a thermal adhesive;
• a thermal spacer outside of the enclosure, wherein the thermal spacer includes a peripheral portion extending beyond the memory die, and the thermal spacer is configured to carry the thermally conductive casing proximate the peripheral portion.

A semiconductor system, comprising:

• a package substrate;
• a thermally conductive casing having a conductive sidewall;
• a plurality of semiconductor dies configured to be carried by the package substrate and at least partially disposed within the thermally conductive casing, the plurality of semiconductor dies including a plurality of memory dies, a logic die having a face, and a thermal spacer stacked relative the logic die and the memory dies, wherein the memory dies are stacked relative to the logic die;
• and
• a driver electrically coupled to the plurality of semiconductor dies via the package substrate;
• wherein the conductive sidewall is attached directly to the face of the logic die by a thermal adhesive.