Reduction of diagnostic fail data volume and tester time using a dynamic N-cover algorithm
Shraddha Bodhe, M. Enamul Amyeen, Clariza Galendez, Houston Mooers, Irith Pomeranz, Srikanth Venkataraman · 2016
This paper presents an algorithm for reducing the test data volume collected by a tester for defect diagnosis of an IC and the tester time. The tester executes the tests and transfers the failing test responses one by one from the tester capture memory to the tester data-logs. While the tester is transferring the fail data, the proposed algorithm analyzes the failing outputs for every test and determines if the test is a potential contributor to the identification of defects. If not, then the test is eliminated from the tester data-logs. Otherwise, the test may replace an existing test or be added as a new test. The addition and replacement of tests continue until the algorithm determines that the fail data transferred to the tester data-logs is sufficient for accurate defect diagnosis. The early termination of the fail data transfer reduces the overall tester time. The effectiveness of the method was verified using real defects in industry fabricated dies. The algorithm was also implemented in a test program library and integrated into a production fail flow for sort data-log optimization. The overhead of the algorithm was minimal, and yielded a 5x reduction in the test data trasfer time.