| 摘要 |
A Defect Leakage Screen Test apparatus and method is introduced to eliminate or reduce steps in the failure analysis process of memory devices, such as DRAM cells, or to eliminate the necessity for the application of a physical failure analysis on the memory device.Special single bit failures due to leakage current, junction current, or threshold leakage current, are characterized by varying the p-well voltage of the memory device during the read operation of the test.The p-well voltage is varied with a test code Initial Program Load (IPL). Additional logic is provided on the memory IC to decode the IPL logic signals.In order to perform the p-well varying test, the memory device is provided with the following: IPL decoding logic; a reference voltage generator; an IPL voltage reference multiplexor; a p-well voltage feed-back circuit; and a differential amplifier circuit. |
