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US 6,650,580 B1Granted
Method for margin testing
AssigneeInternational Business Machines Corporation
InventorGeorge M. Braceras
Life of this patent
Estimating the term…
Abstract
A method for testing semiconductor memory device using an active restore weak write test mode for resistive bitline contacts. During the write margin testing a test signal is used to block the bitline restore devices from turning off during the memory write cycle.
Claims6
A method to perform an active restore weak write margin test in arrays of cells in a memory system comprising the steps of:
- firstly preconditioning the array to a predetermined data state;
- secondly writing into the full array address space an opposite data state than that of the predetermined state along with a write margin test signal;
- thirdly turning off the write margin test signal;
- and
- fourthly reading out the contents of the array to determine which cells failed by not being able to be written.
2 more elements
A method to perform an active restore weak write margin test in arrays of cells in a memory system comprising the steps of:
- firstly preconditioning the array to a predetermined data state;
- secondly writing into the full array address space an opposite data state than that of the predetermined state along with a write margin test signal;
- thirdly turning off the write margin test signal;
- fourthly reading out the contents of the array to determine which cells failed by not being able to be written;
- fifthly writing into the fill array address space the opposite data state of the second step with a write margin test signal in order to stress the opposite data type;
- sixthly turning off the write margin test signal:
- and
- seventhly reading out the contents of the array to determine which cells failed by not being able to be written.
5 more elements
Dependencies are inferred from the claim text.