Semiconductor device including plural chips stacked to each other

1. A method for accessing a plurality of DRAM devices each of the plurality of DRAM devices having a plurality of banks, the plurality of DRAM devices being interconnected to receive common address and command signals, the method comprising:

determining an operating mode for the plurality of DRAM devices;

providing a chip selection address and a bank address with an active command to activate a first bank in a first one of the plurality of DRAM devices and, while the first bank in the first one of the plurality of DRAM devices is activated:

activating a first bank in a second one of the plurality of DRAM devices if the operating mode is determined to be a physical rank address mode;

not activating a first bank in any of the plurality of DRAM devices other than the first one of the plurality of DRAM devices if the operating mode is determined to be a logical rank address mode; and

subsequently providing at least a bank address with a column command to access the first bank in the first one of the plurality of DRAM devices.

2. The method as claimed in claim 1 wherein a chip selection address is also provided with the column command if the operating mode is determined to be the physical rank address mode.

3. The method as claimed in claim 1 wherein a chip selection address is not provided with the column command if the operating mode is determined to be the logical rank address mode.

4. The method as claimed in claim 1 wherein the operating mode is set in a mode register.

5. The method as claimed in claim 4 wherein the operating mode is set in a non-volatile memory.

6. The method as claimed in claim 5 wherein the operating mode is set in a fuse.

7. The method as claimed in claim 1 wherein the plurality of DRAM devices are provided in a stacked configuration connected by through silicon vias.

8. The method as claimed in claim 7 wherein an interposer with external terminals is provided at a stack bottom.

9. The method as claimed in claim 1 wherein a chip selection address is also provided with the column command in the physical rank address mode, and the chip selection address is compared to a predetermined chip address in each of the plurality of DRAM devices to determine the first one of the plurality of DRAM devices.

10. The method as claimed in claim 9 wherein the specific chip address in each of the plurality of DRAM devices is determined through a cascaded connection of the plurality of DRAM devices.

11. A semiconductor device comprising:

a plurality of DRAM devices, each of the plurality of DRAM devices having a plurality of banks, the plurality of DRAM devices being interconnected to receive common address and command signals; and

an interface chip configured to:

provide a chip selection address and a bank address with an active command to activate a first bank in a first one of the plurality of DRAM devices and

subsequently providing at least a bank address with a column command to access the first bank in the first one of the plurality of DRAM devices;

wherein the interconnected DRAM devices are configured to operate in one of:

a physical rank address mode in which the interface chip activates a first bank in a second one of the plurality of DRAM devices while the first bank in the first one of the plurality of DRAM devices is activated; and

a logical rank address mode in which the interface chip does not activate a first bank in a second one of the plurality of DRAM devices while the first bank in the first one of the plurality of DRAM devices is activated.

12. The semiconductor device as claimed in claim 11 wherein the interface chip is further configured to provide a chip selection address with the column command if the DRAM devices are operating in the physical rank address mode.

13. The semiconductor device as claimed in claim 11 wherein the interface chip is configured to not provide a chip selection address with the column command if the DRAM devices are operating in the logical rank address mode.

14. The semiconductor device as claimed in claim 11 wherein the semiconductor device further comprises a mode register and wherein the operating mode is set in the mode register.

15. The semiconductor device as claimed in claim 14 wherein the mode register comprises a non-volatile memory.

16. The semiconductor device as claimed in claim 15 wherein the operating mode is set in a fuse.

17. The semiconductor device as claimed in claim 11 wherein the plurality of DRAM devices are provided in a stacked configuration connected by through silicon vias.

18. The semiconductor device as claimed in claim 17 wherein the semiconductor device comprises an interposer with external terminals, the interposer being provided at a stack bottom.

19. The semiconductor device as claimed in claim 11 wherein the interface chip is also configured to provide a chip selection address with the column command in the physical rank address mode, and wherein each of the plurality of DRAM devices is configured to compare the chip selection address to a predetermined chip address to determine the first one of the plurality of DRAM devices.

20. The semiconductor device as claimed in claim 19 wherein the specific chip address in each of the plurality of DRAM devices is determined through a cascaded connection of the plurality of DRAM devices.