Stacked semiconductor device
A stacked semiconductor device is disclosed that includes a plurality of semiconductor dies. Each die has oppositely disposed first and second surfaces, with pads formed on each of the surfaces. A plurality of through-vias connect respective pads on the first surface to respective pads on the second surface. The through-vias include a first group of through-vias coupled to respective I/O circuitry on the semiconductor die and a second group of through-vias not coupled to I/O circuitry on the semiconductor die. The plurality of semiconductor dies are stacked such that the first group of through-vias in a first one of the plurality of semiconductor dies are aligned with respective ones of at least a portion of the second group of through-vias in a second one of the plurality of semiconductor dies.
1. A packaged semiconductor device comprising:
multiple integrated circuit (IC) chips arranged as a stack, each chip including multiple input/output (I/O) pads, each I/O pad selectively coupled to an input/output (I/O ) circuit;
wherein the I/O pads for each chip in the stack are vertically aligned with corresponding I/O pads in the other stacked chips to define vertically aligned sets of I/O pads;
wherein a given vertically aligned set of I/O pads for the stacked chips is electrically coupled via a conductive path; and
wherein less than all of the I/O circuits corresponding to a given vertically aligned set of I/O pads are electrically coupled to the conductive path.
2. The packaged semiconductor device according to claim 1 , wherein the multiple IC chips comprise dynamic random access memory (DRAM) devices.
3. The packaged semiconductor device according to claim 1 , wherein each path comprises through-silicon-vias formed through each chip.
4. The packaged semiconductor device according to claim 1 , wherein each conductive path is coupled to no more than one I/O circuit.
5. The packaged semiconductor device according to claim 1 , further comprising a programmable element to selectively couple a given I/O pad to a given I/O circuit.
6. The packaged semiconductor device according to claim 5 , wherein the programmable element comprises a programmable fuse.
7. The packaged semiconductor device according to claim 6 , further comprising a serial bus connected to the programmable fuse, wherein the programmable fuse is responsive to a command signal transmitted along the serial bus.
8. A method of operation in a packaged semiconductor device, the packaged semiconductor device having multiple semiconductor chips arranged in a stacked configuration, each chip including multiple input/output (I/O) pads, each I/O pad selectively coupled to an input/output (I/O) circuit, wherein the I/O pads for each chip in the stack are vertically aligned with corresponding I/O pads in the other stacked chips to define vertically aligned sets of I/O pads, each vertically aligned set I/O pads electrically coupled to a vertical conductive path, the method comprising:
in an initialization mode
selectively coupling a given I/O circuit to a given I/O pad; and
in an operating mode
transferring signals along a given conductive path using the selectively coupled I/O circuits, the selectively coupled I/O circuits comprising less than all of the I/O circuits associated with the conductive path.
9. The method according to claim 8 , wherein the selectively electrically coupling a given I/O circuit to a given I/O pad comprises programming a programmable element.
10. The method according to claim 9 , wherein the programming comprises transmitting a command signal to activate a programmable fuse disposed between the I/O pad and the I/O circuit.
11. The method according to claim 10 , wherein the transmitting of a command signal occurs along a serial bus connected to the programmable fuse.
12. The method according to claim 8 , wherein the selectively electrically coupling comprises establishing point-to-point connections between an external signaling path and a given I/O circuit associated with a vertically aligned set of I/O pads.
13. The method according to claim 12 , wherein the selectively electrically coupling comprises connecting no more than one I/O circuit of vertically aligned set of I/O pads to a given vertical conductive path.
14. A memory system comprising:
a memory controller;
multiple memory devices; and
a databus coupling the memory controller to the multiple memory devices in a point-to-point manner; and
wherein the multiple memory devices comprise multiple integrated circuit (IC) chips arranged as a stack, each chip including
multiple input/output (I/O) pads, each I/O pad selectively coupled to an input/output (I/O) circuit;
wherein the I/O pads for each chip in the stack are vertically aligned with corresponding I/O pads in the other stacked chips to define vertically aligned sets of I/O pads;
wherein a given vertically aligned set of I/O pads for the stacked chips are electrically coupled via a conductive path; and
wherein less than all of the I/O circuits corresponding to a given vertically aligned set of I/O pads are electrically coupled to the conductive path.
15. The memory system according to claim 14 , wherein the multiple memory devices comprise dynamic random access (DRAM) memory devices.
16. The memory system according to claim 14 , wherein each conductive path comprises through-silicon-vias formed through each chip.
17. The memory system according to claim 16 , wherein each conductive path is coupled to no more than one I/O circuit.
18. The memory system according to claim 14 , wherein each chip further comprises a programmable element to selectively couple a given I/O pad to a given I/O circuit.
19. The memory system according to claim 18 , wherein the programmable element comprises a programmable fuse.
20. The memory system according to claim 19 , further comprising a serial bus connected to the programmable fuse, wherein the programmable fuse is responsive to a command signal transmitted along the serial bus.