Semiconductor memory device
View Patent ↗Semiconductor memory device includes a cell array including a plurality of unit cells; and a test circuit configured to perform a built-in self-stress (BISS) test for detecting a defect by performing a plurality of internal operations including a write operation through an access to the unit cells using a plurality of patterns during a test procedure carried out at a wafer-level.
1. A semiconductor memory device, comprising:
a cell array including a plurality of unit cells; and
a multi-pattern test circuit configured to:
i.) detect a defect by selectively performing a row pattern test and a column pattern test of said unit cells at a wafer-level,
ii.) repeat inputting/outputting of data by changing a column address based on a row address of the cell array to thereby carry out the row patter test, and
iii.) repeat inputting/outputting of data by changing the row address based on the column address to thereby carry out the column pattern test.
2. The semiconductor memory device as recited in claim 1 , wherein the multi-pattern test circuit comprises:
a test decoder configured to decode signals input via a plurality of address pads to output a test control signal for performing the row pattern test and the column pattern test;
a test pattern generator configured to generate a command control signal and an address control signal according to one of the row pattern test and the column pattern test in response to an output of the test decoder; and
a test command address generator configured to generate an internal test command and an internal address signal in response to an output of the test pattern generator.
3. The semiconductor memory device as recited in claim 2 , further comprising:
a first refresh controller configured to generate a row address for the mow pattern test and the column pattern test response to an output of the test pattern generator; and
a second refresh controller configured to generate a column address and a bank address for the row pattern test and the column pattern test in response to an output of the test pattern generator.
4. The semiconductor memory device as recited in claim 3 , wherein the first and second refresh controllers count addresses for refreshing the cell array in a normal operation.
5. The semiconductor memory device as recited in claim 3 , wherein the test pattern generator comprises:
a pulse generation unit configured to generate the command control signal and a row address increment signal controlling the row address according to one of the row pattern test and the column pattern test;
a column address increment signal generation unit configured to repeatedly activate a column address increment signal for controlling the column address before activation of the row address increment signal according to the row pattern test, and configured to generate the column address increment signal after the column address increment signal is repeatedly activated, according to the column pattern test; and
a bank address increment signal generation unit configured to generate a bank address increment signal for controlling the bank address according to one of the row pattern test and the column pattern test, when the first and second refresh controllers output a signal for resetting the row address and the column address.