The future of delta I/sub DDQ/ testing

The increase in off-state current for deep submicron technologies will make conventional I/sub DDQ/ testing ineffective. An attractive alternative is differential I/sub DDQ/ or /spl Delta/I/sub DDQ/ testing as a function of the test pattern; it is relatively easy to implement it in a production environment and the method can detect I/sub DDQ/ anomalies of a few percent of the off-state current itself. In its simplest form the method is limited by state-dependent leakage current variations. More advanced versions of /spl Delta/I/sub DDQ/ testing can cope with these state-dependencies and are useful for off-state currents in the milliampere range. The presence of state-dependent leakage currents can be utilised to detect large passive defects, which are otherwise undetectable with /spl Delta/I/sub DDQ/. For even higher leak-age currents circuit-specific state-dependencies become the limiting factor and make /spl Delta/I/sub DDQ/ testing ineffective for devices with off-state currents above 100 mA.