Continuous Improvement on the Implementation and Computation of Statistical Yield Limits (SYL) and Statistical Bin Limits (SBL) at Final Test

Statistical Yield Limit (SYL) and Statistical Bin Limit (SBL) are introduced to have criteria on manufacturing lots that are suspected to have yield and/or quality issues that can impact both cost and the customer. Challenges in the calculation and implementation of SYL and SBL through the years are as follows: SYL only for station yield and not device level. No SBL criteria. SYL and SBL to be triggered not only by shop floor system but also in the tester. Handling of SYL for small batch size (<200 units) and large batch size (>200 units). Tedious activities in calculating SYL and SBL. With the challenges mentioned above, the authors assessed and implemented continuous improvement from auto hold trigger via test controller (device level), improved SYL and SBL computation using fixed and robust computation for small batch size and large batch size respectively and dashboard availability for more efficient SYL calculation. These improvements addressed the issues in SYL and SBL, criteria are now per device level, data consistency and lot reject rate on both small batch and large batch size is resolved. Shorter TPT in calculation and implementation of SYL and SBL is also achieved by creating a dashboard for automatic calculation of SYL.