Method and apparatus for testing memory cells for data retention faults
AssigneeInternational Business Machines Corporation
InventorsR. Dean Adams, Aneesha P. Deo, Kamran Zarrineh
Life of this patent
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Abstract
A method for testing memory cells for data retention faults is disclosed. A first logical value is stored in a first cell, and a second logical value is stored in a second cell of a memory device. The second cell shares the same column with the first cell. The bitlines associated with the first and second cells are prevented from being precharged before the second cell can be read. After the second cell has been read repeatedly, the first cell is read, and the bitlines associated with the first and second cells are precharged. At this point, a data retention fault is determined to have occurred if the first cell does not contain the first logical value.
Claims11
A method for testing memory cells for data retention faults, said method comprising:
- storing a first logical value in a first cell of a memory device;
- storing a second logical value in a second cell of said memory device, wherein
- said second cell shares a same column with said first cell;
- preventing bitlines associated with said first and second cells from being precharged;
- reading said second cell repeatedly followed by a read of said first cell;
- precharging said bitlines associated with said first and second cells;
- and
- detecting a data retention fault has occurred if said first cell does not contain said first logical value.
A memory tester for testing memory cells for data retention faults, said memory tester comprising:
- means for storing a first logical value in a first cell of a memory device;
- means for storing a second logical value in a second cell of said memory device, wherein said second cell shares a same column with said first cell;
- means for preventing bitlines associated with said first and second cells from being precharged;
- means for reading said second cell repeatedly followed by a read of said first cell;
- means for precharging said bitlines associated with said first and second cells;
- and
- means for detecting a data retention fault has occurred if said first cell does not contain said first logical value.
A computer program product for testing memory cells for data retention faults, said computer program product comprising:
- program code means for storing a first logical value in a first cell of a memory device;
- program code means for storing a second logical value in a second cell of said memory device, wherein said second cell shares a same column with said first cell;
- program code means for preventing bitlines associated with said first and second cells from being precharged;
- program code means for reading said second cell repeatedly followed by a read of said first cell;
- program code means for precharging said bitlines associated with said first and second cells;
- and
- program code means for detecting a data retention fault has occurred if said first cell does not contain said first logical value.
Dependencies are inferred from the claim text.