A Comparison of Functional and Pin-to-Pin Screening Data During Five Thousand Hours of Integrated Circuit Life Testing

This report evaluates and compares two electrical screening tests for integrated circuits, functional and pin-to-pin, over a period of 5,000 hours of operational life testing. Of a sample of 1,000 integrated circuits, 71% were initially identified by the functional screen as high qua'lity devices as opposed to 28% by the pin-to-pin screen. In addition, only 10 devices from the sample were commonly rejected by both tests. Further analysis revealed that 18 functional unacceptable devices were classified as pin-to-pin high quality devices and that 31 pin-to-pin unacceptable devices were classified as functional high quality. In general, the number of test failures observed remained constant during the first 5,000 hours of life testing. However, in the case of the load resistor test (pin-to-pin) and the output current test (functional), the number of test failures decreased as the testing time increased. An examination of the screening data after 5,000 hours of life testing showed essentially no change in the quality distribution of the sample as measured by the functional tests. However, the pin-to-pin screen showed a significant change in the sample distribution, with a number of circuits going from the high quality grouping to the commercial grouping.