Enhanced memory reliability in stacked memory devices

1. A method for improving reliability in a stacked memory device comprising a plurality of data memory integrated circuits coupled together and a parity memory integrated circuit coupled to the plurality of data memory integrated circuits, the method comprising:

(A) during a write operation to a particular memory address of each of the plurality of data memory integrated circuits:

(i) inputting a plurality of data words each associated with one of the plurality of data memory integrated circuits,

(ii) performing a first parity calculation on the plurality of data words to generate a parity word,

(iii) writing each of the data words to the particular memory address of its associated memory integrated circuit in the plurality of data memory integrated circuits, and

(iv) writing the parity word to the particular address of the parity memory integrated circuit; and

(B) during a read operation from the particular memory address in each of the plurality of data memory integrated circuits:

(i) reading the data words from the particular memory address of each of the plurality of data memory integrated circuits;

(ii) reading the parity word from the particular memory address of the parity memory integrated circuit,

(iii) performing a second parity calculation on the plurality of data words and the parity word to generate a corrected data word;

(iv) replacing up to one of the plurality of data words with the corrected data word; and

(v) outputting the corrected plurality of data words.

2. The method of claim 1 wherein:

the stacked memory device further comprises a controller integrated circuit coupled to the plurality of data memory integrated circuits and the parity memory integrated circuit, and

the controller integrated circuit further comprises a write logic circuit and a read logic circuit.

3. The method of claim 2 , wherein:

each of the plurality of data memory integrated circuits outputs a control signal indicative of the presence or absence of an error in the data word read from that memory integrated circuit,

each control signal is coupled to the read logic circuit, and

the control signals are used to control the second parity calculation.

4. The method of claim 3 , wherein:

the first parity calculation to generate the parity word is a bit-by-bit XOR function of all of the bits in the plurality of data words,

the second parity calculation is performed when one of the control signals indicates the presence of an error in the data word read from the associated data memory integrated circuit,

the second parity calculation is a bit-by-bit XOR function of all of the bits in the parity word and all of the bits in the data words from the data memory integrated circuits where their respective control signals indicate the absence of an error, and

the data word resulting from the second parity calculation replaces the data word from the memory integrated circuit where the error was indicated.

5. The method of claim 2 , wherein:

the first parity calculation to generate the parity word is a bit-by-bit XOR function of all of the bits in the plurality of data words,

the second parity calculation to generate the corrected data word is performed when there is an error in a data word read from a data memory integrated circuit,

the second parity calculation is a bit-by-bit XOR function of all of the bits in the parity word and all of the bits in the data words from the data memory integrated circuits where there is no error, and

the corrected data word replaces the data word from the data memory integrated circuit where the error occurred.

6. The method of claim 1 , wherein:

the first parity calculation to generate the parity word is a bit-by-bit XOR function of all of the bits in the plurality of data words,

the second parity calculation to generate the corrected data word is performed when there is an error in a data word read from a data memory integrated circuit,

the second parity calculation is a bit-by-bit XOR function of all of the bits in the parity word and all of the bits in the data words from the data memory integrated circuits where there is no error, and

the corrected data word replaces the data word from the data memory integrated circuit where the error occurred.

7. The method of claim 6 , wherein:

the data memory integrated circuits are DRAM integrated circuits,

the parity memory integrated circuit is a DRAM integrated circuit,

the stacked memory device further comprises a single package, and

the data memory integrated circuits and the parity memory integrated circuit are coupled together with through silicon via (TSV) technology.

8. The method of claim 5 , wherein:

the data memory integrated circuits are DRAM integrated circuits,

the parity memory integrated circuit is a DRAM integrated circuit,

the stacked memory device further comprises a single package, and

the data memory integrated circuits and the parity memory integrated circuit are coupled together with through silicon via (TSV) technology.

9. The method of claim 4 , wherein:

the data memory integrated circuits are DRAM integrated circuits,

the parity memory integrated circuit is a DRAM integrated circuit,

the stacked memory device further comprises a single package, and

the data memory integrated circuits and the parity memory integrated circuit are coupled together with through silicon via (TSV) technology.

10. The method of claim 3 , wherein:

the data memory integrated circuits are DRAM integrated circuits,

the parity memory integrated circuit is a DRAM integrated circuit,

the stacked memory device further comprises a single package, and

the data memory integrated circuits and the parity memory integrated circuit are coupled together with through silicon via (TSV) technology.

11. The method of claim 2 , wherein:

the data memory integrated circuits are DRAM integrated circuits,

the parity memory integrated circuit is a DRAM integrated circuit,

the stacked memory device further comprises a single package, and

the data memory integrated circuits and the parity memory integrated circuit are coupled together with through silicon via (TSV) technology.

12. The method of claim 1 , wherein:

the data memory integrated circuits are DRAM integrated circuits,

the parity memory integrated circuit is a DRAM integrated circuit,

the stacked memory device further comprises a single package, and

the data memory integrated circuits and the parity memory integrated circuit are coupled together with through silicon via (TSV) technology.

13. A method for improving reliability in a stacked memory device comprising a plurality of data memory integrated circuits coupled together, the method comprising:

(A) incorporating a parity memory integrated circuit coupled to the plurality of data memory integrated circuits in the stacked memory device;

(B) during a write operation to a particular memory address of each of the plurality of data memory integrated circuits:

(i) inputting a plurality of data words each associated with one of the plurality of data memory integrated circuits,

(ii) performing a first parity calculation on the plurality of data words to generate a parity word,

(iii) writing each of the data words to the particular memory address of its associated memory integrated circuit in the plurality of data memory integrated circuits, and

(iv) writing the parity word to the particular address of the parity memory integrated circuit; and

(C) during a read operation from the particular memory address in each of the plurality of data memory integrated circuits:

(i) reading the data words from the particular memory address of each of the plurality of data memory integrated circuits;

(ii) partitioning each of the data words into a plurality of data sub-words according to bit position in the data words;

(iii) reading the parity word from the particular memory address of the parity memory integrated circuit,

(iv) partitioning the parity words into a plurality of parity sub-words according to the same bit positions as in the data words;

(v) for each partition of data-sub words and the parity sub-word grouped according to their bit positions:

(a) performing a second parity calculation on the plurality of data sub-words and the parity sub-word to generate a corrected data sub-word, and

(b) replacing up to one of the plurality of data sub-words in each partition with the corrected data sub-word of that partition

(vi) reconstructing the corrected data sub-words into corrected data words corresponding to the original data words; and

(vii) outputting the corrected plurality of data words.

14. The method of claim 13 wherein:

the stacked memory device further comprises a controller integrated circuit coupled to the plurality of data memory integrated circuits and the parity memory integrated circuit, and

the controller integrated circuit further comprises a write logic circuit and a read logic circuit.

15. The method of claim 14 , wherein:

each of the plurality of data memory integrated circuits outputs a control signal indicative of the presence or absence of an error for each partitioned data sub-word read from that memory integrated circuit,

each control signal is coupled to the read logic circuit, and

the control signals are used to control the second parity calculation for their associated partitions.

16. The method of claim 15 , wherein:

the first parity calculation to generate the parity word is a bit-by-bit XOR function of all of the bits in the plurality of data words,

the second parity calculation to generate the corrected data sub-word is performed for each partition when one of the control signals indicates the presence of an error in a data sub-word in that partition,

the second parity calculation for each partition is a bit-by-bit XOR function of all of the bits in the parity sub-word and all of the bits in the data sub-words from the partition where their respective control signals indicate the absence of an error, and

the corrected data sub-word resulting from the second parity calculation replaces the data sub-word from the partition where the error was indicated.

17. The method of claim 14 , wherein:

the first parity calculation to generate the parity word is a bit-by-bit XOR function of all of the bits in the plurality of data words,

the second parity calculation to generate the corrected data sub-word is performed for each partition when there is an error in a data sub-word in that partition,

the second parity calculation for each partition is a bit-by-bit XOR function of all of the bits in the parity sub-word and all of the bits in the data sub-words from the partition where there is no error, and

the corrected data sub-word resulting from the second parity calculation for each partition replaces the data sub-word from the partition where the error occurred.

18. The method of claim 13 , wherein:

the first parity calculation to generate the parity word is a bit-by-bit XOR function of all of the bits in the plurality of data words,

the second parity calculation to generate the corrected data sub-word is performed for each partition when there is an error in a data sub-word in that partition,

the second parity calculation for each partition is a bit-by-bit XOR function of all of the bits in the parity sub-word and all of the bits in the data sub-words from the partition where there is no error, and

the corrected data sub-word resulting from the second parity calculation for each partition replaces the data sub-word from the partition where the error occurred.

19. The method of claim 18 , wherein:

the stacked memory device further comprises a single package, and

the data memory integrated circuits, the parity memory integrated circuit, and the controller integrated circuit are coupled together with through silicon via (TSV) technology.

20. The method of claim 17 , wherein:

the stacked memory device further comprises a single package, and

the data memory integrated circuits, the parity memory integrated circuit, and the controller integrated circuit are coupled together with through silicon via (TSV) technology.

21. The method of claim 13 , wherein:

the stacked memory device further comprises a single package, and

the data memory integrated circuits and the parity memory integrated circuit are coupled together with through silicon via (TSV) technology.

22. A method for improving reliability in a stacked memory device comprising a plurality of data memory integrated circuits coupled together, a first parity memory integrated circuit coupled to the plurality of data memory integrated circuits, and a second parity memory integrated circuit coupled to the plurality of data memory integrated circuits and the first parity memory integrated circuit, the method comprising:

(A) during a write operation to a particular memory address of each of the plurality of data memory integrated circuits:

(i) inputting a plurality of data words each associated with one of the plurality of data memory integrated circuits,

(ii) performing a first parity calculation on the plurality of data words to generate a parity word and an error correction word,

(iii) writing each of the data words to the particular memory address of its associated memory integrated circuit in the plurality of data memory integrated circuits,

(iv) writing the parity word to the particular address of the first parity memory integrated circuit, and

(v) writing the error correction word to the particular address of the second parity memory integrated circuit; and

(B) during a read operation from the particular memory address in each of the plurality of data memory integrated circuits:

(i) reading the data words from the particular memory address of each of the plurality of data memory integrated circuits;

(ii) reading the parity word from the particular memory address of the first parity memory integrated circuit,

(iii) reading the error correction word from the particular memory address of the second parity memory integrated circuit,

(iv) performing a second parity calculation on the plurality of data words, the parity word, and the error correction word to generate a corrected data word;

(v) replacing up to two of the plurality of data words with the corrected data word, and

(vi) outputting the plurality of data words.

23. The method of claim 22 wherein:

the stacked memory device further comprises a controller chip coupled to the plurality of data memory integrated circuits, the first parity memory integrated circuit and the second parity memory integrated circuit, and

the controller chip further comprises a write logic circuit and a read logic circuit.

24. The method of claim 23 wherein:

each of the plurality of data memory integrated circuits outputs a control signal indicative of the presence or absence of an error in the data word read from that memory integrated circuit,

each control signal is coupled to the read logic circuit, and

the control signals are used to control the second parity calculation.