Method and apparatus for localizing point defects causing leakage

Abstract

Method for localizing point defects causing column leakage currents in a non-volatile memory device, said device including a plurality of memory cells arranged in rows and columns in a matrix structure, the columns being connected to drain regions by first contacts, source diffusions, and metal lines which connect the source diffusions to each other by second contacts. The method includes the steps of modifying the memory device in order to eliminate a part of the first contacts and all the second contacts, and to form third contacts, which connect the metal lines to drain regions in rows wherein the first contacts have been eliminated, making the source diffusions independent of each other and halving the initial number of the memory cells; sequentially biasing the single columns of the matrix; sequentially biasing the single rows of the matrix, keeping biased one column; localizing a memory cell which presents the point defects, when the leakage current flow occurs.