A reliability statistics perspective on the pitfalls of standard Wafer-Level Electromigration Accelerated Test (SWEAT)

Standard Wafer Level Electromigration Accelerated Test (SWEAT) has become a common fast wafer level reliability test for electromigration in industry. However, its ability to detect changes in processes and its correlation with conventional electromigration test result has come under close scrutiny. From the perspective of reliability statistics, SWEAT also has other pitfalls that render its test results questionable. In this work, these pitfalls are highlighted, and alternative wafer-level electromigration tests are discussed. The arguments that the SWEAT is not appropriate for evaluation of electromigration of metal lines are presented. SWEAT as a tool to evaluate electromigration lifetime of metal lines is not recommended unless the pitfalls are seriously looked at.