32 Nm Device Leakage Failure Discriminant Method Of The Accuracy Of The Research

Yield ramp is very important to Semiconductor fabrication. The testing and analysis based on the test chips and test structures can provide the fail rate of each process module and indicate the root cause of the failing defects. Thus it can help to ramp up the yield. So, it is extreme important to get the correct clarification of whether the test structure fails. The paper found a confusing issue that the SEM images say there should be short failure, but the test results do not show any fail. Through defect overlay analysis and their test values statistics clarification, the issue is located as the incorrect fail spec setting of the test structures. And in the following modules check, it is found that most modules have such issue. Thus the conclusion is the old fail spec setting doesn’t work in the advanced technology node any more. In the mean time, a method and flow is provided to check the common issues as met.For an effective defining test structure short failure, the paper offers three proposals, and then verifies them one by one by experiment and analysis. Based on the Resistance of test structure is relevant to the test values of the short failure, the paper get the initial solution through the statistics analysis. After that, the theory analysis and mathematical deduction prove the solution. Thus the solution and analysis flow are based on the solid theory base. The final solution is the effective defining test structure short failure can be achieved through setting the short failure spec to 2x of the max normal Resistance of the responding module-design parameter group.The solution works very well in the real project. At last, the paper foresees the potential challenges in the next technology node and beyond, and proposes the specific solution improvement and thinking.