Circuit and method for testing embedded DRAM circuits through direct access mode

1. A method for testing a semiconductor device comprising the steps of:

providing a semiconductor device including an embedded dynamic random access memory (eDRAM) for storing data;

determining if the semiconductor device is in test mode;

if the semiconductor device is in the test mode, determining whether to use BIST logic circuitry or direct access mode logic circuitry; and

performing a dekct test on the semiconductor device using either the BIST logic circuitry or the direct access mode logic circuitry;

wherein if the direct access mode logic circuitry is used, the method further comprises:

multiplexing data from the external tester to a bus width of the semiconductor device;

multiplexing addresses from the external tester, the addresses specifying the memory cells to be tested; and

outputting to the external memory tester test results of the memory cells.

2. The method as in claim 1 , wherein if the BIST logic circuitry is used, the method further comprises:

initiating a BIST test from a logic tester;

receiving an end of test (EOT) signal at the logic tester;

receiving a pass/fail signal from the BIST logic circuitry; and

determining if the semiconductor device is good or bad.

3. The method as in claim 1 , further comprising the step of generating a fail bit map from the test results and calculating redundancy algorithms.

4. The method as in claim 3 , further comprising the step of repairing defective memory cells using the fail bit map and redundancy alogrithms.

5. The method as claimed in claim 1 wherein the eDRAM includes a plurality of memory cells and a test controller for testing the plurality of memory cells to determine if the cells are defective, the test controller including built-in self-test (BIST) logic circuitry for performing tests and for interfacing to a logic tester and direct access mode logic circuitry for interfacing the eDRAM with an external memory tester.